Better os compatibility

[htjb]

Resolving #8 and some install issues on Windows hopefully. Also adding tests for the different OS.

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (dce5bb0) 98.26% compared to head (68598b5) 98.26%.

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Additional details and impacted files

@@           Coverage Diff           @@
##           master      #21   +/-   ##
=======================================
  Coverage   98.26%   98.26%           
=======================================
  Files          10       10           
  Lines         635      635           
=======================================
  Hits          624      624           
  Misses         11       11           

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[htjb]

Okay, I now have working tests on windows, mac and linux. Hopefully the windows pip install should be fixed too (I was having issues with the function that parses the readme in setup.py to get the version number).

Having some issues on mac and windows with tkinter.

[htjb]

Hmm going to move tkinter setup to a separate issue since it looks complicated!