Fixes an issue where you couldn't turn off kickstart accel while boat driving.
Fixes an issue where the "Lua.Boat_SpeedMul" map header wouldn't work.
Fixes weird interactions with tricks, as well as some minor visual bugs. Changelog: Tricks will now properly function when boat driving. Made the 3D tilting tilt not as strong as before. Added new "speedmul" and "speedstack" options. Fixed stumble/tumble not rotating when boat driving, as well as it not squashing and stretching. Hid the stumble indicator since you can't stumble coming out of boat driving.
Fixed a possible lua error where it would attempt to use a value that wouldn't exist.
Fixes kickstart acceleration not applying while boat-driving
