MetadataBundle.addFromPaths() now consults modification times before attempting
to cache a given corpus path.


git-svn-id: http://music21.googlecode.com/svn/trunk@3566 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Improved metadata caching.

git-svn-id: http://music21.googlecode.com/svn/trunk@3567 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Improved metadata path caching.

git-svn-id: http://music21.googlecode.com/svn/trunk@3568 5c16147e-a200-11de-b0cc-ab0ad15e60d0