Update imports and put fallbacks in place
Use new style exceptions
Use new style octal literals
Use six' iteritems compatibility function
Use Python 2.6 built-in next
Unroll context managers of deprecated contextlib.nested
Use io module for reading README, no BOM stripping
Add Python 3 classifier to setup.py
Replace unicode
Port raw_input to input
Replace call of has_key with in-check
Listify Python 3 iterators
Raise proper Exception, not string