python 3 compatibility
More python3 compat
Use less magic to look up subclasses of Helpers
Create some shims for py3k
No implicit string casting
Bail out on invalid messages
Explicitly cast everything to lists
More idiomatic test for data

python3 breaks because this is an empty array of bytes, not the empty
string
Apply kludges to format args
Merge pull request #27 from richo/features/python3

Python 3 support