fog of war (early), random gems, sonar no factory

1. Started adding pieces for new fog of war system, but not implemented
2. temporary random generation of gems from stones at level start. This
will be overridden by procedural level generation system, but I wanted
to get this in so I could see how the game played without me knowing
where all the gems were
3. FIX: When upgrading from factory to Sonar, you no longer retain the
benefits of the factory