Python interface

Here is a go at a python interface to SpatialKappa. There is one extra java class and a python package - see the python directory. The file python/INSTALL should explain all, and things should work fairly transparently. I have found out how to get Java launched from within the py4j library, and the setup.py file in the python directory should automatically install the SpatialKappa jar in a place where it can be found by python. This has been tested on Ubuntu 12.04.  Comments welcome!