commented simple-clic move (to enable later GUI for rotation)
piece orientation by selecting, moving mouse and then unselecting
keyboard-triggered piece rotation with mouse
draw an image under the currently selected piece to indicate that it can be rotated
draw different images under selected piece depending on whether mouse rotation is active
added dummy assets
added forgotten dummy assets
finished rotate by drag; debug using up and down arrow
better drag for rotation
better computation of piece rotation; new, clearer assets
drag n rotate does not put an offset anymore
merged with master
Merge pull request #99 from CyberCRI/rotate-pieces

Rotate pieces