Upgrade movement change.

Gave the movement for upgrade objects a nice effect. I like it and it's
nice. If you want to see something cool, move that change  -
2*Math.sin(pos.x*Math.PI/180) to the x component on bullets when they're
updated. Super cool effects....could do something with that later.
System in place for fire rate upgrade
Consolidate code shared by all entities
Cleanup code for the day, Upgrade collide works