Knuckles changes:

- Buffed crouch landing; lasts slightly shorter and cuts speed less
- Support for swimming! Knuckles has slightly different glide controls when he has swim sprites underwater
- Improved glide controls in 2D mode
- Super Knuckles perks: land from a glide or latch onto a wall to generate a shockwave and damage nearby enemies
- Refactored skid dust
- Made super sparks use FF_FULLBRIGHT
- Added P_SpawnSkidDust and P_Earthquake to Lua