Adds the look of 2D selection tool, doesn't do anything with the selection currently.
Click now selects single tile.
Adds selection rectangle storage. Refs #30 @1h up to now.
Ability to clear selection. Refs #30 @30m.

 I can't believe I wasted 30 minutes of my life doing this.
Ability to clear selection. Refs #30 @30m.

 I can't believe I wasted 30 minutes of my life doing this.
Merge remote-tracking branch 'origin/master'