Reorganized metadata modules code layout.


git-svn-id: http://music21.googlecode.com/svn/trunk@3549 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Migrated corpus/metadataCache/metadataCache.py logic into metadata.py.


git-svn-id: http://music21.googlecode.com/svn/trunk@3550 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Cleaned up variable names in metadata.py.


git-svn-id: http://music21.googlecode.com/svn/trunk@3551 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Added some multiprocessing workflow utilities to metadata.py.


git-svn-id: http://music21.googlecode.com/svn/trunk@3552 5c16147e-a200-11de-b0cc-ab0ad15e60d0
Renamed Chord._components to Chord._notes everywhere.


git-svn-id: http://music21.googlecode.com/svn/trunk@3553 5c16147e-a200-11de-b0cc-ab0ad15e60d0