Added appveyor for tests on Windows

Author: ogenstad

appveyor.yml

@@ -0,0 +1,20 @@
+environment:
+
+  matrix:
+    - PYTHON: "C:\\Python27"
+    - PYTHON: "C:\\Python34"
+    - PYTHON: "C:\\Python35"
+
+init:
+  - set PATH=%PYTHON%\Scripts;%PATH%
+
+install:
+  - "%PYTHON%\\python.exe -m pip install tox"
+
+build: off
+
+test_script:
+  - tox
+
+artifacts:
+  - path: dist\*