Bullet time sound effects and progress bar.

- Added bullet time sound effects and assets to bullet time mode
start/stop.
- Added pie-chart progress bar functionality.
- Used pie-chart progress bar for bullet-time mode.
- Tweaked bullet time length, regen rate, and minimum for usage.
Bullet time basic fixes.  Ideas updated.

- Bullet time fixes for handling restart button presses.
- Bullet time fixes for when alt+tabbed.
- Added disableAllMovement function for more gracefully handling
pauses/restarts/etc.
- Added colour variation on bullet time progress bar.