Mostly a controls update

Fixed up the jumping controls, smoothed out speed and turning by
including acceleration, changed how stamina works so that it is less
network intensive, made galloping use stamina, made the horse not wander
when being ridden (super annoying), temporarily disabled "resistance"
code as it was a bit buggy, made it so you can't attack the horse while
riding it, added controls for stopping the horse, and added a debug
function for convenience in testing. Have fun, and don't forget to test
and report bugs!