Features added
-Burst mode added to rifle.  You can now select single, burst, or automatic fire rates.
-Added new toxic slime enemy.  You cannot hide from toxic slime, you must jump over them.
-You can now pause the game by pressing "P".

Bug Fixes:
-Fixed issue where footsteps weren't registering properly.
-Fixed issue where layers were not in correct order.
-Fixed issue with unexpected alpha channel flickering.