Replace onelint with prettier, switch to 2 space indent

.editorconfig

@@ -0,0 +1,12 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2

.eslintignore

@@ -1,5 +1,3 @@
 testdata
-lib/3rdparty
-examples
 node_modules
 coverage

.eslintrc.js

@@ -1,18 +1,15 @@
-module.exports = {
-    extends: [
-        'onelint'
-    ],
-    rules: {
-        'no-const-assign': 2
-    },
-    env: {
-        es6: true
-    },
-    parserOptions: {
-        ecmaVersion: 2017,
-        ecmaFeatures: {
-            experimentalObjectRestSpread: true
-
-        }
-    }
+const config = {
+  extends: ['pretty-standard']
 };
+
+if (process.stdin.isTTY) {
+  // Enable plugin-prettier when running in a terminal. Allows us to have
+  // eslint verify prettier formatting, while not being bothered by it in our
+  // editors.
+  config.plugins = config.plugins || [];
+  config.plugins.push('prettier');
+  config.rules = config.rules || {};
+  config.rules['prettier/prettier'] = 'error';
+}
+
+module.exports = config;

.prettierignore

@@ -0,0 +1 @@
+package.json

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}

package.json

@@ -20,10 +20,12 @@
     "assetgraph": "5.4.0",
     "coveralls": "^3.0.0",
     "eslint": "5.7.0",
-    "eslint-config-onelint": "4.0.0",
+    "eslint-config-pretty-standard": "2.0.0",
+    "eslint-plugin-prettier": "3.0.0",
     "istanbul": "^0.4.2",
     "lodash.pluck": "3.1.2",
     "mocha": "^5.1.0",
+    "prettier": "1.14.3",
     "unexpected": "^10.26.0",
     "urltools": "0.4.1"
   },