Floatless

This mod simply disables standard creative flight for all players. Doesn't really do anything to check that the client isn't cheating it, so don't use this for moderation; we're just making this to change how a private creative server is played.

KNOWN ISSUE: When in spectator mode, players will simply fall through the world, as that gamemode relies on the same flight attribute. We can probably fix this but we aren't going to yet.