Many many sm. changes in anticipation of PY3

Also iPython improvements
Merge branch 'master' of https://github.com/cuthbertLab/music21

Conflicts:
	music21/test/lastResults.txt
More PY3 changes and MultiprocessTest
more PY3 improvements
del obsolete. more py3 fixes
python3 multiprocess test WORKS!
:Merge branch 'master' into mei

Conflicts:
	music21/converter/__init__.py
WIP-MEI: New: _filterNamespace() Function to Avoid URI-Prefixed Tag Names

Using this function allows importing with ElementTree in a way that does
not prefix every MEI tag with the XML namespace's URI. Even though this is
a bit of a hack, that would have been very clumsy, and without much gain!