[Adv.Inv.] Make "move all" actually move all. [CR]

It erroneously assumed the player needed to be able to pick up the items, limiting the move-all action to moving only what would fit in the player's available volume and weight.

Note that I'm not entirely sure if this is the correct fix, nor do I guarantee that g->drop should be used for putting the items in the target square. The current method appears to be stolen from a pickup handler, and so I may have just broken that (no idea how generic this method is).

Further note there's still one known bug: once you use the move-all function once, it won't work again until you close the AIM and reopen it. This may have something to do with activity stacking the Adv. Inv. activity before performing the move *iff* the option to keep it open after move-all is selected.

Currently just looking for more eyes on the subject, and maybe a hint as to a better solution.