Eliminated scfg_reloaded (not possible now that we always recycle to reload

configuration changes).
If BBS_OPT_NO_EVENTS gets set during run-time, event_thread() goes into a
sleep loop until it is unset (or the server is terminated).
Eliminated BBS_OPT_KEEP_ALIVE (use ctrl/sockopts.cfg instead).
semfile_list_check() handles initialization of timestamp, if 0.