Merge pull request #25 from DavidPartouche/master

Fixed broken build with latest rust update (use 'foo' = 'bar' syntax err...
Remove forgotten debugging println
Closes #26
Not specifiying dimensions on win32 now results in CW_USEDEFAULT
Close #11
Fix & add some comments for win32
Cleanup temporary objects in case of error during creation on win32
See #10
Remove call to glViewport after win32 initialization