Faster Random

Major structural changes as a result of #41. Not much is user-facing (aside from a few small changes to the JVM pop-up.) There shouldn't be any noticeable changes between 4.0.x and 4.1.0.

As a result, Faster Random now:

Has a smaller file size (due to removing MixinExtras)

Implements CheckedRandom's splitters fully.

LocalRandom has gone back to using ThreadLocalRandom

Faster Random no longer announces it's presence due to the main entrypoint being deleted.