pets getting "stuck" trying to reach inaccessible objects

pets getting "stuck" trying to reach inaccessible objects
Incorporate a slightly modified version of a patch submitted by <Someone> back in June.  The basic problem, which I noticed again this past
weekend, is that pets with a high apport value can still try to get to
objects when there's no path to the object.  The patch extends the
can_reach_food function to be used for any object, renaming it to
can_reach_location, and adds a could_reach_item function for doing point
checks.  This also removes any chance of a pet dragon, for example, eating
something underwater.