[Coldstuff] To all cold admins out there: bug fixes

[xmath]

Bug fixes for everybody who admins a coldcore-derived server, 
especially if people can get programmer access:

1. $connection.write lacks (> .perms(sender()) <);
just add that as first line (already done at the Cold Dark)

2. $scheduler.cancel allows any preempted (non-suspended) task to be 
killed by anyone. I think only admins should be allowed to do that 
(maybe the user, but I seriously doubt that, since a task killed in 
middle of execution could leave things in an inconsistent state). Add 
an elseif-clause, like:
   } else if (!$sys.is_system(sender())) {
       throw(~perm, sender() + " may not kill task " + task_id);
   }

3. Users can be trapped in a $location with no means of escape, by 
overriding $location.will_leave to always throw an error. Solution: 
allow the manager of an object to eject it. On a side note: perhaps 
eject should allow ejecting objects to their .home() instead. And why 
not add an argument to .move_to to remove the will-checks (will_move, 
will_leave, will_arrive) if the sender() is properly authorized. 
eject can then just check perms and determine the right destination, 
and call the unchecked version of .move_to. Saves code-duplication.
An @eject command would be nice too (and @eject! for a rude version, 
in case the offending place *is* your home)

Here's a write-up (tested on a server, although not thoroughly) that 
does it all, and allows admins to refuse ejecting from a location.
http://www.nubz.org/move-eject.cold.txt

4. There are problems with changing the parents of an object. I'll 
give a fix as soon as I've figured out what exactly goes wrong and 
how to fix it.

  - xmath