Suddenly, an update!

The after-the-gamejam-ended-fixing-small-things-that-I-should've-fixed-before-but-didn't-because-I-was-oh-so-done-with-this-thing update.

• Mouse sensitivity now affects both vertical and horizontal mouse movement.
• Explosion sound doesn't play from direction opposite of explosion.
• Grenade box becomes invisible when player picks it up.