Some more small, incremental changes to the score system.

In addition to destroying enemies, picking up items (ammo, boost and key items) now contributes to your score as well!

Hopefully this will provide a bit of an incentive to go after those hard to reach pickups.

I'm also doing some work under the hood to facilitate future improvements to the score system, like a score multiplier. (Coming soon!)

Changes in v0.379:

• Score is now awarded for picking up items.
• Add UI notification when toggling FPS display.
• Add UI notification when toggling color grading.