Release version v1.9.3.
Release version v.1.9.3
Initial 2.0 commit
few changes for PyPi
Revert to 1.9.3 version -- will do 2.0 as a separate branch.
quarterLength selectively produces Fractions
optional Fractions almost everywhere
added chordify test
all offsets etc. are rational or power of 2 floats

Speed reduction is less than 1%.  Made up in test suite by optimizing
abc/translate.
OrderedDict for CHORD_TYPES
Merge branch 'version2'

Conflicts:
	music21/base.py
	music21/corpus/metadataCache/core.json
	music21/duration.py
	music21/note.py
	music21/sites.py
	music21/stream/__init__.py
metadataCache/cor.json fix
ignore .orig files.
Merge branch 'master' into version2
Merge remote-tracking branch 'upstream/master' into StaffLines