lists: cache the len()
lists: cache the len()

This makes the gol.py about 100x faster.

buchuki/pyjaco,mattpap/py2js,qsnake/py2js,chrivers/pyjaco,qsnake/py2js,buchuki/pyjaco,buchuki/pyjaco,mattpap/py2js,chrivers/pyjaco,chrivers/pyjaco