Update: replace all os.path.normcase with os.path.normpath

[ngorden]

This will fix filenames being forced into lowercase on Windows. ( Fixes #242 )

I have done basic happy path testing on Windows, Mac and Linux and have not found any unintended side effects

From the python docs:

normcase: On Windows, convert all characters in the pathname to lowercase, and also convert forward slashes to backward slashes. On other operating systems, return the path unchanged.

normpath: Normalize a pathname by collapsing redundant separators and up-level references so that A//B, A/B/, A/./B and A/foo/../B all become A/B. This string manipulation may change the meaning of a path that contains symbolic links. On Windows, it converts forward slashes to backward slashes.