Core formatting cleanup

Got rid of a buttload of typos in the core and cleaned up a bunch of stuff (see the commit message for more info).

Just making a pull request for opinions to see if it's worth merging. I know some people might heavily reject such changes (but given the pretty bad state of the nulldc remnants, I hope an exception will be made in this instance).

If there's a strong objections to this, then I'll just discard the change :)