When hovering over something (or things) in the world, display information about them.

[Nixill]

This information would display in the bottom left, above the coordinates (which would be compacted to one line), and would go (upwards from the coordinates) from the tile up. Two examples are in the comments.

Also, this is completely needed for things without sprites (see #15).

[Nixill]

For example, in this image:

The following info would be displayed:

Tile: Boss floor
x: -1 / y: -8

[Nixill]

For second example, in this image:

The following info would be displayed:

Trap: Bounce trap down
   type: 1 / subtype: 2
Item: Freeze enemies scroll
   type: scroll_freeze_enemies / bloodCost: No / saleCost: No / singleChoice: No
Tile: Boss floor
x: 6 / y: -4