Too Many Asteroids! (Optimisation Update)

​I've finally been able to get to cutting down some wasted frame times to do with asteroids! Previously, an entry level gaming computer would get about 5-10fps when playing with 5000+ asteroids in a small area. Now you can expect between 100-200fps in that same area.

Better PCs can expect upwards of 400fps in Instant Action.

Changes:

-Asteroids now only update every half second or so

-Asteroids now slow down if they're going too fast every update

-Harvesters now mine far more effectively, and don't panic with too many asteroids. (This could still be optimized more)

-An already mined asteroid now spawns mined asteroids when split! (It's now possible to mine the universe dry)

Go even further beyond, pilots!