Replace python3 compile action with 2to3 action

Run a 2to3 code analysis on python code about to be committed instead of
compiling it as python3. The advantage being that you get a diff view of changes
you should make before committing of all the changes rather than the first
compile error that the python3 interpreter hit.
Merge pull request #43 from koddsson/master-2to3

Replace python3 compile action with 2to3 action