Magic Cube

On second thought, come back to Vector. The problem: before we had the potentially blocking function 'effectFinished' inside our synchronized block.

1) add missing call to BlockController.onPause() / onResume() to the Tutorial activity
2) rearrange BlockController's error reporting to make the case where the MessageSender thread has died separate
3) in such case, resurrect the thread
4) simplify and harden the EffectMessageSender

Correct height of the tutorial dialog.

Add Mirror 2x2 tutorials.

Increase NODE_RATIO, i.e. the height/width ratio of the DistortedNode behind the object (before with 1.4, if one scrambled the Mirror Cube and made it the largest possible, corners were cut off form the top and bottom)

Mirror Cubes: re-enable meshes; update meshes.

Mirror Cubes: make them still more off-center.

Mirror Cubes: make them a bit more off-center.

Mirror Cubes: add meshes and icons.

Add Mirror Cube 2x2 and 3x3.