Remove Twisted dependency
Fix test runner for Travis
Remove unused instance variable from Clock
Merge pull request #10 from hynek/remove-twisted-dependency

Remove Twisted dependency

Replace the usage of Twisted’s Clock by a minimal replacement.
Add PyPy and Python 3.3 to CI

Use tox for actual testing.
Merge pull request #11 from hynek/toxify

Add PyPy and Python 3.3 to CI