diff --git a/package-lock.json b/package-lock.json
index 91d0808..c9628a6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -65,6 +65,68 @@
         "glob-to-regexp": "0.3.0"
       }
     },
+    "@rollup/pluginutils": {
+      "version": "3.0.9",
+      "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-3.0.9.tgz",
+      "integrity": "sha512-TLZavlfPAZYI7v33wQh4mTP6zojne14yok3DNSLcjoG/Hirxfkonn6icP5rrNWRn8nZsirJBFFpijVOJzkUHDg==",
+      "dev": true,
+      "requires": {
+        "@types/estree": "0.0.39",
+        "estree-walker": "^1.0.1",
+        "micromatch": "^4.0.2"
+      },
+      "dependencies": {
+        "braces": {
+          "version": "3.0.2",
+          "resolved": "https://registry.npmjs.org/braces/-/braces-3.0.2.tgz",
+          "integrity": "sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==",
+          "dev": true,
+          "requires": {
+            "fill-range": "^7.0.1"
+          }
+        },
+        "estree-walker": {
+          "version": "1.0.1",
+          "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-1.0.1.tgz",
+          "integrity": "sha512-1fMXF3YP4pZZVozF8j/ZLfvnR8NSIljt56UhbZ5PeeDmmGHpgpdwQt7ITlGvYaQukCvuBRMLEiKiYC+oeIg4cg==",
+          "dev": true
+        },
+        "fill-range": {
+          "version": "7.0.1",
+          "resolved": "https://registry.npmjs.org/fill-range/-/fill-range-7.0.1.tgz",
+          "integrity": "sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==",
+          "dev": true,
+          "requires": {
+            "to-regex-range": "^5.0.1"
+          }
+        },
+        "is-number": {
+          "version": "7.0.0",
+          "resolved": "https://registry.npmjs.org/is-number/-/is-number-7.0.0.tgz",
+          "integrity": "sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==",
+          "dev": true
+        },
+        "micromatch": {
+          "version": "4.0.2",
+          "resolved": "https://registry.npmjs.org/micromatch/-/micromatch-4.0.2.tgz",
+          "integrity": "sha512-y7FpHSbMUMoyPbYUSzO6PaZ6FyRnQOpHuKwbo1G+Knck95XVU4QAiKdGEnj5wwoS7PlOgthX/09u5iFJ+aYf5Q==",
+          "dev": true,
+          "requires": {
+            "braces": "^3.0.1",
+            "picomatch": "^2.0.5"
+          }
+        },
+        "to-regex-range": {
+          "version": "5.0.1",
+          "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
+          "integrity": "sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==",
+          "dev": true,
+          "requires": {
+            "is-number": "^7.0.0"
+          }
+        }
+      }
+    },
     "@semantic-release/commit-analyzer": {
       "version": "5.0.2",
       "resolved": "https://registry.npmjs.org/@semantic-release/commit-analyzer/-/commit-analyzer-5.0.2.tgz",
@@ -166,6 +228,12 @@
         "@types/enzyme": "3.1.9"
       }
     },
+    "@types/estree": {
+      "version": "0.0.39",
+      "resolved": "https://registry.npmjs.org/@types/estree/-/estree-0.0.39.tgz",
+      "integrity": "sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==",
+      "dev": true
+    },
     "@types/events": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/@types/events/-/events-1.2.0.tgz",
@@ -344,6 +412,7 @@
       "resolved": "https://registry.npmjs.org/align-text/-/align-text-0.1.4.tgz",
       "integrity": "sha1-DNkKVhCT810KmSVsIrcGlDP60Rc=",
       "dev": true,
+      "optional": true,
       "requires": {
         "kind-of": "3.2.2",
         "longest": "1.0.1",
@@ -3686,7 +3755,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.1.1",
@@ -3737,7 +3807,8 @@
         "balanced-match": {
           "version": "0.4.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "bcrypt-pbkdf": {
           "version": "1.0.1",
@@ -3752,6 +3823,7 @@
           "version": "0.0.9",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "inherits": "2.0.3"
           }
@@ -3760,6 +3832,7 @@
           "version": "2.10.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "hoek": "2.16.3"
           }
@@ -3768,6 +3841,7 @@
           "version": "1.1.7",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "balanced-match": "0.4.2",
             "concat-map": "0.0.1"
@@ -3776,7 +3850,8 @@
         "buffer-shims": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "caseless": {
           "version": "0.12.0",
@@ -3793,12 +3868,14 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "combined-stream": {
           "version": "1.0.5",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "delayed-stream": "1.0.0"
           }
@@ -3806,22 +3883,26 @@
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "core-util-is": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "cryptiles": {
           "version": "2.0.5",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "boom": "2.10.1"
           }
@@ -3861,7 +3942,8 @@
         "delayed-stream": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "delegates": {
           "version": "1.0.0",
@@ -3893,7 +3975,8 @@
         "extsprintf": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "forever-agent": {
           "version": "0.6.1",
@@ -3915,12 +3998,14 @@
         "fs.realpath": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "fstream": {
           "version": "1.0.11",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "graceful-fs": "4.1.11",
             "inherits": "2.0.3",
@@ -3976,6 +4061,7 @@
           "version": "7.1.2",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "fs.realpath": "1.0.0",
             "inflight": "1.0.6",
@@ -3988,7 +4074,8 @@
         "graceful-fs": {
           "version": "4.1.11",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "har-schema": {
           "version": "1.0.5",
@@ -4016,6 +4103,7 @@
           "version": "3.1.3",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "boom": "2.10.1",
             "cryptiles": "2.0.5",
@@ -4026,7 +4114,8 @@
         "hoek": {
           "version": "2.16.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "http-signature": {
           "version": "1.1.1",
@@ -4043,6 +4132,7 @@
           "version": "1.0.6",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "once": "1.4.0",
             "wrappy": "1.0.2"
@@ -4051,7 +4141,8 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "ini": {
           "version": "1.3.4",
@@ -4063,6 +4154,7 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "number-is-nan": "1.0.1"
           }
@@ -4076,7 +4168,8 @@
         "isarray": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "isstream": {
           "version": "0.1.2",
@@ -4149,12 +4242,14 @@
         "mime-db": {
           "version": "1.27.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "mime-types": {
           "version": "2.1.15",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "mime-db": "1.27.0"
           }
@@ -4163,6 +4258,7 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "brace-expansion": "1.1.7"
           }
@@ -4170,12 +4266,14 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "mkdirp": {
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -4230,7 +4328,8 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "oauth-sign": {
           "version": "0.8.2",
@@ -4248,6 +4347,7 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "wrappy": "1.0.2"
           }
@@ -4277,7 +4377,8 @@
         "path-is-absolute": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "performance-now": {
           "version": "0.2.0",
@@ -4288,7 +4389,8 @@
         "process-nextick-args": {
           "version": "1.0.7",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "punycode": {
           "version": "1.4.1",
@@ -4326,6 +4428,7 @@
           "version": "2.2.9",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "buffer-shims": "1.0.0",
             "core-util-is": "1.0.2",
@@ -4370,6 +4473,7 @@
           "version": "2.6.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "glob": "7.1.2"
           }
@@ -4377,7 +4481,8 @@
         "safe-buffer": {
           "version": "5.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "semver": {
           "version": "5.3.0",
@@ -4401,6 +4506,7 @@
           "version": "1.0.9",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "hoek": "2.16.3"
           }
@@ -4434,6 +4540,7 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "code-point-at": "1.1.0",
             "is-fullwidth-code-point": "1.0.0",
@@ -4444,6 +4551,7 @@
           "version": "1.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "safe-buffer": "5.0.1"
           }
@@ -4458,6 +4566,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "2.1.1"
           }
@@ -4472,6 +4581,7 @@
           "version": "2.2.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "block-stream": "0.0.9",
             "fstream": "1.0.11",
@@ -4527,7 +4637,8 @@
         "util-deprecate": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "uuid": {
           "version": "3.0.1",
@@ -4556,7 +4667,8 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },
@@ -8451,6 +8563,12 @@
       "integrity": "sha1-Ywn04OX6kT7BxpMHrjZLSzd8nns=",
       "dev": true
     },
+    "picomatch": {
+      "version": "2.2.2",
+      "resolved": "https://registry.npmjs.org/picomatch/-/picomatch-2.2.2.tgz",
+      "integrity": "sha512-q0M/9eZHzmr0AulXyPwNfZjtwZ/RBZlbN3K3CErVrk50T2ASYI7Bye0EvekFY3IP1Nt2DHu0re+V2ZHIpMkuWg==",
+      "dev": true
+    },
     "pify": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
@@ -9357,13 +9475,31 @@
       }
     },
     "rollup-plugin-sourcemaps": {
-      "version": "0.4.2",
-      "resolved": "https://registry.npmjs.org/rollup-plugin-sourcemaps/-/rollup-plugin-sourcemaps-0.4.2.tgz",
-      "integrity": "sha1-YhJaqUCHqt97g+9N+vYptHMTXoc=",
+      "version": "0.6.0",
+      "resolved": "https://registry.npmjs.org/rollup-plugin-sourcemaps/-/rollup-plugin-sourcemaps-0.6.0.tgz",
+      "integrity": "sha512-w8VaINTIqa2pbQEgDpkbPYdTc4Y2btgdJg4Tqwr8mtpdRgvEXprNWsLoCJphe4NRFKqeMedBjZ4m2FbrEtA3dQ==",
       "dev": true,
       "requires": {
-        "rollup-pluginutils": "2.0.1",
-        "source-map-resolve": "0.5.1"
+        "@rollup/pluginutils": "^3.0.9",
+        "source-map-resolve": "^0.6.0"
+      },
+      "dependencies": {
+        "atob": {
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/atob/-/atob-2.1.2.tgz",
+          "integrity": "sha512-Wm6ukoaOGJi/73p/cl2GvLjTI5JM1k/O14isD73YML8StrH/7/lRFgmg8nICZgD3bZZvjwCGxtMOD3wWNAu8cg==",
+          "dev": true
+        },
+        "source-map-resolve": {
+          "version": "0.6.0",
+          "resolved": "https://registry.npmjs.org/source-map-resolve/-/source-map-resolve-0.6.0.tgz",
+          "integrity": "sha512-KXBr9d/fO/bWo97NXsPIAW1bFSBOuCnjbNTBMO7N59hsv5i9yzRDfcYwwt0l04+VqnKC+EwzvJZIP/qkuMgR/w==",
+          "dev": true,
+          "requires": {
+            "atob": "^2.1.2",
+            "decode-uri-component": "^0.2.0"
+          }
+        }
       }
     },
     "rollup-plugin-typescript2": {
diff --git a/package.json b/package.json
index ae2ab39..fa589e0 100644
--- a/package.json
+++ b/package.json
@@ -113,7 +113,7 @@
     "rollup": "^0.56.3",
     "rollup-plugin-commonjs": "^9.0.0",
     "rollup-plugin-node-resolve": "^3.0.0",
-    "rollup-plugin-sourcemaps": "^0.4.2",
+    "rollup-plugin-sourcemaps": "^0.6.0",
     "rollup-plugin-typescript2": "^0.12.0",
     "rxjs": "^5.5.6",
     "rxjs-marbles": "^2.3.1",