.travis.yml: add python 3.3
fall back to io.StringIO if cStringIO is not available
setup: add six
cStringIO: use six.moves
.itervalues -> six.itervalues
Add tests for serialize_number in binary encoding
Sneak in some buffer b's.
setup: inform pip off the Python 3 support
get_git_version: print a string
Add tests for compact format
Make compact serialization Py3proof
/ -> //
Force non-unicode passphrases
More b's, less u's
Allow unicode public key
Fix serialize_number problems with gmpy
Use BytesIO instead of StringIO
Eliminate basestring
Fix tests
Add unicode exceptions