implemented SIG membership control, Delete SIG, and the "shell" for the

System Administration menu; also added "Post & Go Topics" as an option for the
post box in conferencing

TODO

@@ -2,19 +2,20 @@ Lots!
 
 - Unimplemented functions on the SIG Administration page:
   Set SIG Features (sigadmin, command=F)
-  Membership Control (sigadmin, command=M)
-  Delete SIG (sigadmin, command=DEL)
 
 - Implement SIG invitations ("Invite" button on the profile).
 
+- Unimplemented functions in the system admin menu:
+  Set Global Parameters
+  View/Edit Banned Users
+  User Account Management
+  (More stuff needs to be added, I'm just not sure what.)
+
 - Should we provide the sysadmin the ability to disable SIG creation for
   non-admin users?  Maybe there needs to be a "global" set of levels that
   aren't hardcoded.  Where do they get stored?  The database?  (Maybe the
   nice shiny new "globals" table?)
 
-- There's no system admin functionality AT ALL.  We need to have this stuff
-  before we go live.  (It plugs into the Administrative SIG features.)
-
 - Unimplemented functions on the Top page:
   Customize Sideboxes