Make the project PyPI-compatible

I wrap the whole thing into a `tastypie_actions` module, and provide some packaging info so that this can be pushed onto PyPI.

Things to note:

* The README file is rewritten in RestructuredText so that it can be rendered correctly on PyPI. I changed some formatting in it, please feel free to revert anything if you don't like them.
* `author_email` needs to be filled in `setup.py`
* A version number is needed, so I kind of arbitrarily add a `__version__ = '1.0'` line. Please correct it if you consider it inappropriate.