UNTELL
======

Syntax: (untell <simple-predication>) ::=
        (untell [<relation-name> <instance> <value>])

UNTELL means, that all bindings will be broken.
The predication that will be used has to be fully
instanciated, i.e. that no unbound logical variables
should be used. The anonymus variable
can be used to set an instance-value relation on
indefinite.
UNTELL returns T, if the value is deleted, otherwise
NIL.

Example: >(untell [place Buckingham-Palace London])
         T

The value London will be deleted in this example!