pAI whispering

...session of an item

* fixed storage.dm to properly call ..() in its dropped() function
* Added whisper.dm to pai so pAIs can whisper
* Modified pai/say.dm say_quote to have argument for italicizing text
* Use the held_by variable to ensure that somone carrying a pAI can hear them whisper while they move, previously the eavesdrop/listener/watch code did not handle this well

When an item is equipped() or dropped() it calls update_holder() which updates held_by for the item.

Thanks to Nodrak for all his help