Allow setup.py install with python3

These changes arose from 2to3.
Fallback to ISO-8859-1 if UTF-8 fails

Python3 fails to read corpus/haydn/opus103/movement1.zip with
UTF-8.

Warning: I know almost nothing about text encoding, so I am not
certain this is the best fix.  However, without it, python3 fails
to parse the score; this fix at least allows us to extract musical
information from that file.
Merge pull request #68 from gperciva/master

python3 compatibility
Merge remote-tracking branch 'upstream/master' into mei