Add Python language support

Recently, Topcoder SRM has launched an experimental support of python 2.6.
For the sake of python coders --- the greed plugin should support python, too!

This is an experimental implementation of python support feature.
In the practice room, it works anyway, but it seems there are lots of things needed to do.
Still, this is yet *unstable* -- Please don't merge it until it becomes stable and is tested enough.

Please refer to the commit message of 501f95e for the technical details.

Next steps would be:

- add python unit test code
- enrich README
- code cleanup (refactor duplicated things..)

Thanks!