- New rectangle selection tool. Hold mouse button to create selection, release to finish it. You cannot draw outside of the selection.
- The selection can be moved around, and if Shift is pressed, selected content gets moved too. Currently cannot be moved outside the canvas.
- You can copy the selection with Ctrl + C, and paste it on a new selection with Ctrl + V.
- Added tile mode. Basically draws the canvas 8 more times in all directions.
