Changes throughout Moodle to remove any reserved words from the

Moodle tables.

ie user -> userid in many tables, plus in user_students
   start -> starttime and end -> endtime

I've just done all this as carefully as I could ... I don't think
I missed anything but it's pretty intensive work and I'd be fooling myself
if I didn't think I'd missed a couple.

Note that this version should pretty much be able to bootstrap itself
using PostgreSQL now ... but this is untested

admin/admin.php

@@ -67,7 +67,7 @@
             }
         }
 
-        $admin->user = $user->id;
+        $admin->userid = $user->id;
         $admin->id = insert_record("user_admins", $admin);
         $admins[] = $user;
     }