Add: Overheat bar to turret

Added an overheat bar to the turret. It grows orange, and when it
reaches its threshold, it will turn to red. While the bar is red, no
missiles can be shot from the turret.
Fix: moved the heat bar to the top of screen below the score
Add: chandelier texture and sound mute button to main menu
Add: Credits
Add: quotes to credits
Random Fixes:

Added arrows to store. Added high score tracker. changed point values
for
unlimited missiles