Replaced the player controller

-Changed the original player controller with a modular FPS plugin. Have tweaked code and values to work 
with the current system.
-Player also can now walk up slopes, zoom in camera (which has a nice effect when you release objects) 
and has a head bob for some polish.

Added in a button door system

-A button door system has been implemented. When the player or a physics cube is on the button, it will 
open the doors linked to the button. Will be good for setting up physics based puzzles with gravity.