Fixed extremely long bleedout problem

Since bleeding slows down, this resulted in an exponential deduction of
bleedrate and thus blood so it never actually reached zero. This
addresses that with a simple check.
Revision of script exit sequence

Module shutdowns now use OnScriptExit for saving data and OnGameModeExit
is reserved for just notifying that the server is safe to shut down
completely. This removes the need to call save functions from one
OnGameModeExit call since hooks are used instead.