Click-holding on a card then immediately releasing now properly changes the
cursor from a closed hand back to an open hand

if cards in multiple zones are selected, don't create drag items for the ones you're not supposed to move

Revealing a library to a player now grants that player permission to drag cards out of that library onto his own table. This permission is revoked by shuffling the library. The zone view window tracks content changes of the zone for as long as the permission lasts so that card ID changes are kept track of. This hopefully fixes issues #5 and #12.

stop card tap/untap animation in CardItem::resetState() to avoid unfinished animation during zone change

optionally destroy tokens on zone change; added multi arrows; card menu changes; arrow fixes; initial commit for attachCard code