pickup into quiver

pickup into quiver

     Despite lack of feedback from the beta testers about it, add the code
which tries to stack an object being added to inventory with the quiver
before trying with other carried objects.  Only matters to user if quiver
is non-empty and one or more other slot(s) are compatible with it, but
that's not uncommon for someone who starts a rogue by splitting the initial
daggers into separate wield and throw slots.  Firing a dagger from quiver
and then having it merge with wielded weapon instead of back into quiver
when picked back up leads to tedious inventory manipulation.  Assigning
different names to the two stacks solves this, but can't help when picking
up an unnamed item which is otherwise compatible.  (A rogue with starting
daggers wouldn't encounter that since unnamed ones won't be sufficiently
identified to stack, but any character who just gathers unID'd daggers and
uses them for both melee and throwing has a chance of running into the
"picked up into less desireable slot" trap whenever new ones are found.)