Added a "EVENT" string command to force a timed event to execute. If the

event code is not passed as a parameter, the available (enabled) timed events
are displayed and the sysop can choose the proper one by number.
This change requires the latest (as of now) load/sbbsdefs.js.
Also updated a lot of the parameter prompting to actually indicate the kind of
parameter string that is being asked for (e.g. "QWKnet ID" instead of just
"Parameter(s)").