Add windows CI using choco

Resolves #62

.travis.yml

@@ -2,7 +2,14 @@ language: python
 
 matrix:
     include:
-        # - python: 3.6
+        - os: windows
+          language: sh
+          python: 3.7
+          before_install:
+              - choco install python3
+              - export PATH="/c/Python37:/c/Python37/Scripts:$PATH"
+              - python -m pip install --upgrade pip wheel
+
         - python: 3.7
           dist: xenial
           sudo: required