3D FPS

Three significant changes made:

1. New input mapping and event for the Left Shift keyboard key. New script behavior to handle when the left shift key is held down, it enables a "power boost" (move around more quickly).

2. Modified Level 1 to have complexity -- must kill the walking enemy in order for it to drop the key, to exit the level.

3. Modified Level 2 (boss level) to have additional complexity, multiple enemies, and modified enemy behavior.