Improve interface for collecting items

Currently the only way to collect an item is to walk over it and wait for the popover to appear. This inadequate for many reasons, mainly:

1. Player must move to a tile to pick up an item
2. Player can't pick up an item they've dropped without moving
3. Popover appears and blocks player view when they're not interested in picking up the item

AC

1. Appropriate interface for collecting items has been designed
2. New interface for collecting items has been implemented