A little TODO list for fifteen puzzle

• Fix tiles sizing. They are integer-sized, gaps between them are all equal, but overall the grid it aligned to top left, so at certain applet sized it may end up having different outer margins.

  

• Port away from org.kde.kquickcontrols/ColorButton or port the button itself to QQC2.

• ColorButton does not support drag&drop. Worth filing a separate and proper bug report (feature request) on https://bugs.kde.org

• Grid size control should have at least a lower boundary.

• Grid size could've been a more convenient segment button if we had one in QML. Just a few options in range 3..10 would be enough. Do we really need a spinbox with support for an arbitrary large boards?

• Usability / gameplay feature. The only one gameplay mechanic in this game is to move tiles. Player moves them by pressing on tiles directly beside an empty tile. But when player clicks on a tile that is on the same row or column as the empty tile, all tiles in between should move too. !170 (merged)

• The applet could track steps/clicks count in addition to a time tracker. Reducing number of steps is one of the two possible objectives of this game.

• UI: Don't show "Solved!" message until the last tile's animation is finished. Stop the timer, disable the UI and wait for completion instead.