Add tox configuration
Merge pull request #212 from DasIch/add-tox

Add tox configuration
Added .tox to .gitignore
Fixed a check that broke pypy
Merge pull request #213 from Lukasa/luk-sprint-branch

Sprint: Misc fixes.
Cleanup up some imports
file -> open for 3.x support.  This fixes #152
Make dump() work Python 3.3
Merge pull request #214 from Lukasa/luk-sprint-branch

Sprint: More misc fixes