Reward having more planets more than massive planets

[zstewar1]

Currently the screensaver seems to lean towards just starting with more planets and letting them fall into the center and make a single large mass. This is probably because it's easier to get more points by having more mass than by having more planets. This should probably be tuned somehow.

Some ideas:

• Constant multipliers for both mass and number of planets so we can boost or reduce one or the other
• Exponential powers on each, so the value of adding more mass vs adding more planets is nonlinear.
• Adjust scoring over time, so having more planets towards the end of the simulation is more valuable than having a lot of planets at the beginning (rewarding keeping them around)

These should all be included in the configurable parameters from #3