Fix interface to the Stanford tagger: in both Python 2 and 3 cases, make sure we're writing the temporary file in the appropriate encoding, then likewise decoding the tagger output.
simplifications suggested by @heatherleaf
make encoding more explicit (and not default to None)
Merge pull request #360 from alexrudnick/fix_stanford_unicode

Fix interface to the Stanford tagger so it works on Python 2 and 3