Fix a few more small memory leaks
item_info: Cache last item information to speed up repeat lookups (e.g. if used to get descriptions for mouse hover).
Use item_info module to display hover over descriptions of items in an item list.
Use item_info module to display hover over descriptions of items in storage.
Use item_info module to display hover over descriptions of items in iventory.
elwindows: added new display callback called before the main body.  Can be used to draw outside any scissor region.
Use item_info module to display hover over descriptions of items in a ground bag. Unfortunately, item_uids are not current sent by the server so not all look-ups work.
Merge git://github.com/raduprv/Eternal-Lands