Made two minor adjustments

- Previously, if an orb was still in motion when the game was exited, it wouldn't store the experience on subsequent level ups. This has been fixed, along with updated logic to handle experience bar overflow  from this

- Found the root cause of a performance update with the experience bar particles, so they should spawn more smoothly now. The reason is funny: I was adding a particle to an object, then duplicating the object when making new particles. This new object would have all the old particles in it + 1, and would in turn be duplicated too. This created an unstable infinitely stacking nesting effect that could rapidly cause slowdown. Woops.