This function deletes a KVP attribute from an object or character. If no object or character is specified, the attribute is deleted from the object or character that bears the currently executing MUDL script. Otherwise, the attribute is deleted from the specified object or character. Note that the attribute is only deleted from that particular loaded copy of the entity, it is not deleted in the version saved on disk. So, the next time the entity loads the attribute will be back.
The attribute is always deleted from the currently executing MUDL proc, or if it's on a foreign object or character, from the lowest-numbered MUDL proc on that object or character.
This function returns true if the attribute actually exists (and therefore was deleted), false if there was no such attribute.