ready to tox.
replace implements declarations to implementer decorator.
add py32,py33 env to tox
ommit dependency to Elixir on py3k.
skip tests with Elixir on py3k.
fix invalid syntax of unicode literal on py3.2
upgrade dependencies versions to support py3
add supporting versions.
Merge branch 'py3k' of https://github.com/aodag/repoze.who-sqlalchemy