music21 v. 3 release (3.1.0)

dist/dist.py

@@ -16,12 +16,13 @@
 
 1. update the VERSION in _version.py and the single test cases in base.py and 
      in case of major version changes freezeThaw.JSONFreezer.jsonPrint if this wasn't done already.
-2. for a major change, run 
+2. for a major change, run in Py3
     `corpus.cacheMetadata(['core', 'virtual'], verbose=True)`.
     every once in a while run corpus.corpora.CoreCorpus().metadataBundle.rebuild() 
     (40 min on MacPro) -- either of these MAY change a lot of tests in corpus, metadata, etc.
     so don't skip the next step!
 3. run test/multiprocessTest.py  for Python2 AND Python3
+3.5 run test/testLint.py and fix any lint errors
 4. commit and then check test/testSingleCoreAll.py results on Travis-CI
      (normally not necessary, because it's slower and mostly duplicates multiprocessTest, 
      but should be done before making a release).  Done automatically by Travis-CI on GitHub commit