Build Python wheels for windows on travis (#160)

* upgrade for windows on travis

* Install python on travis windows, update readme, update tests

* update readme, travis config and clean code

* install python inside cibuildwheel run

* use register to get python path

* fixes from review

* fix pip version

* use nuget for instal python

* clean code

* Update cibuildwheel/windows.py

Co-Authored-By: Joe Rickerby <joerick@mac.com>

* fixes from review

* Final bits of tidy up

.travis.yml

@@ -27,6 +27,15 @@ matrix:
         - brew update
         - brew outdated python || brew upgrade python
 
+    - os: windows
+      language: shell
+      before_install:
+       - choco install python3 --version 3.6.8 --no-progress -y
+      install:
+       - C:\\Python36\\python -m pip install -r requirements-dev.txt
+      script:
+       - C:\\Python36\\python ./bin/run_tests.py
+
 install: $PYTHON -m pip install -r requirements-dev.txt
 
 script: $PYTHON ./bin/run_tests.py