Be able to change Character Data attributes in Lua#57

Say that you wanted to make a character that gets a movement speed or a knockback buff after using a certain move, it would be really useful if we could change character stats mid-game

Marking planned but far due to the fact that we only have options like speed and gravity (and a few more) overridable behind the scenes. Those will be exposed sooner rather than later but a full exhaustive list will be further into the future.

These overridable functions combind with the custom attributes in the CharacterData are what we use to pull off a speed buff such as Wraster’s slip stream.