add force rankup and prestige
add update notification on join
more reliable legacy server version check
added permissions: rankup.admin (grants rankup.checkversion, rankup.reload, rankup.force, and rankup.notify), rankup.notify (receive update notiifications on login), rankup.force (force a player to rankup or prestige)
improve operations and make them extendable more easily and let other plugins add operations, like requirements
move requirements/operations out of ranks class as they will be used in prestiges