Fix bugs found on GameSurge

Fix bugs found on GameSurge

* Remove unused ARCH_REVISION macro in Makefile.am

* Fix !trim <userlevel> <duration> (so it does not trim ALL users)

* Properly allow owners to set levels to 501

* Set "deopped" when we deop the person who changed modes

* Mark the first user in a channel as a chanop (fixes a spurious
  HACK(4) for newly registered channels).

* Document user level ranges for the TRIM command.

* Document user-level-based SET options as being such (rather than
being multiple-choice options).
git-archimport-id: srvx@srvx.net--2004-srvx/srvx--devo--1.3--patch-11