Distribute python sources with the package

Distributing the source and not the compiled files ensures it works on all
platforms and python versions. Add postinstall script to compile them
after install.

All versions and files had to be hardcoded since you can't use shell
expansion in package.json script blocks.
Run tests on both python 2 and 3
Make travis tests work with source distributions and py3
Merge pull request #9 from thusoy/python-3

Add support for python 3