CustomAnvil

Better enchant limit & remove protocolib (#109)

Simplify item level limit code by deleting "default level" and using enchantment's default level instead allow max level 0 for "can't use it" and -1 for "default maximum" made the enchantment limit gui reflect the above change

Also removed force protocolib in config as hopefully should be unnecessary. It is still in the plugin in case something go wrong, which seems unlikely as never been necessary as far as I remember