Added fixes to help the test suite pass under Ubuntu.


git-svn-id: http://music21.googlecode.com/svn/trunk@3586 5c16147e-a200-11de-b0cc-ab0ad15e60d0
More cross-platform tweaks.


git-svn-id: http://music21.googlecode.com/svn/trunk@3587 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Added doctests for more set-theoretic operators on MetadataBundle.


git-svn-id: http://music21.googlecode.com/svn/trunk@3588 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Added a new function to common:

    common.relativepath()

This is intended as a safe, platform-independent wrapper for os.path.relpath,
which returns the relative path on Unix-like systems, and returns the original
path on Windows, in order to avoid problems where the current working directory
and the path under consideration are rooted at differently-lettered drives.


git-svn-id: http://music21.googlecode.com/svn/trunk@3589 5c16147e-a200-11de-b0cc-ab0ad15e60d0