fix a crash in the parser for USE orders when no item name was given.
WIP: Familiars check for combat spells in the magician's list of spells, too.
https://bugs.eressea.de/view.php?id=1660
This does not work, because set_combatspell later uses knowsspell to make sure the spell is one the familiar has.
Merge pull request #77 from badgerman/bug-1660

Bug 1660