fnmatch and its OS specific behaviour

Another funny quicks about Python fnmatch algorithm.

I was playing around with Pydicom, and it has a function called: get_testdata_files which calls get_files from its data_manager.py which calls fnmatch from fnmatch.py which is part of Anaconda 3 lib. However, fnmatch itself is quicky in that it will enforce case matching on Linux but relax this on Windows.  So When calling the Pydicom function with “JPEG” will only match fewer test file on ubuntu (e.g. Travis-CI) vs when testing this on Windows (my dev machine).

Use fnmatchcase are probably a better idea.