harmony.py & fromMxObjects.py : bug fix to allow parsing of chord symbols with degree-alter, degree-type, and degree-value tags (in response to David Bolton's post to m21 list)

git-svn-id: http://music21.googlecode.com/svn/trunk@3368 5c16147e-a200-11de-b0cc-ab0ad15e60d0
add support for complex repeat bracket numbers in spanner.py

git-svn-id: http://music21.googlecode.com/svn/trunk@3369 5c16147e-a200-11de-b0cc-ab0ad15e60d0
freezing of MIDI (.volume objects) works.  Give more compact images for .png generation in Lilypond

git-svn-id: http://music21.googlecode.com/svn/trunk@3370 5c16147e-a200-11de-b0cc-ab0ad15e60d0