Eliminated recycle_sem from startup structures (not used anywhere).

Added shutdown_now to startup structures, used for nice shutdowns
(when server isn't in use) as opposed to terminate, which is immediate.
shutdown semaphores files are only acted on when server not in use.
Bugfix: server.client_add/remove() methods now adjust the service's client
counter accordingly so static services (like ircd.js) won't be recycled or
shutdown while in use (any more).