Miscellaneous Improvements

Changes:
- Near-perfect levelnames.xml
- Updated readme (thank you to iZackefx for volunteering to test as many
unknown values as possible in-game)
- Various bugfixes (mostly, but not all, NSMB2-related)

Reggie Next is not dead! Lots of work - mostly research of
currently-unknown NSMB2 settings - is being done behind the scenes right
now, and there are some very big commits coming up in the near future.
Keep watching for those :)