Bette Collision System

> Remapped jump key to 'z', and added 'x'
>> x cancels upwards momentum if you are going up, and makes you fall
faster when you are already heading down.
> New function to handle all the conditions necessary to check for
collision, and returns an intuitive string.
> Removed a lot of the seizures that happen around bounds
> Interesting glitch; platform A can be passed through if you time 'x'
correctly.