Remove blank function
Don't try to swap stash stacks when dropping from inventory

Possibly related to #1232. This ensures that if we drop an inventory
item on a non-empty stash slot, it will be added to an empty slot and
not treated as if we're rearranging stash contents.
Allow equipping items dragged in from stash/vendor
Merge pull request #1234 from dorkster/menus

Drag & drop tweaks