Snap cards on a case-by-case basis back to pre-drag position if their edge exceeds the canvas.
Fix card shake on cards that were dragged into valid positions.
Reveal trashcan after holding mousedown on a card for a half second.
Make trashcan area full width at bottom of canvas.
Delete selected cards that are dropped in the trash area.
Fade out deleted cards.
Deleted expanding.js CSS overrides.
Fix laggy drop validation caused by mouseup event being bound dozens/hundreds of times.
Bind drop-handling mouseup exactly once.
Note end of big each loop.
Prevent CSS transform parsing and drag checking from happening after a single click.
Restore transitions on dragged cards.