Convert greenery into a package
o Pull fsm.py and lego.py symbols into greenery namespace in __init__.py
o Enable relative imports from main.py and in "__main__" test sections of fsm.py
  and lego.py on direct execution, by manually loading module.
o Convert all intra-package imports to explicit relative imports
o Avoid some O(N) performance for large FSMs
o Added distutils based setup.py packaging
o Set __version__ to '1.0', specified separately in simple _version.py
o Tested in Python 2.7/3.3
Merge pull request #8 from pjkundert/feature-package

Convert greenery into a package