Create a way to update mappings automatically

[OroArmor]

Will likely use a java version of https://gist.github.com/LambdAurora/b987fbb580827566ef1bf52bdde441de

[LambdAurora]

My only worry with a Java version of this is stuff like the ASM lib, and stuff to parse tiny/Enigma mappings.

When I looked at those it looked way over-complicated, and possibly-breaking with time (looks at ASM lib being very strict on bytecode version).