Accurate Stamina Display

Fixes the stamina meter display on the HUD, so it more accurately represents your current stamina percentage.

In the original game, the meter appears full until you are at about 90% stamina, and it appears empty when you still have about 20% stamina left.

Includes configuration settings for added visual cues:

Turns the meter red when you are exhausted (can't sprint).
Gradually changes the meter's base color as you inhale TZP for endurance. (orange -> yellow -> green)