Magic Cube

Bugfix

When we're leaving the Tutorial activity, unblock everything.

Make it impossible to launch more than one Tutorial screen at a time.

Progress with RubikControl.

BlockController: Unblock after 3 seconds.

Fix the long-standing problem that putting app to the background would not stop the 'solving' counter.

Fix the reddening the Lock icon.

Fix a rare crash.

Introduce a BlockController - a watchdog which makes sure the Touch and UI blocks do not take too long.
If it detecs a long block, it unblocks and reports the situation to Crashylytics.

Add a 'give up' dialog - if one made at least 10 moves when solving and presses a 'back' button, one needs to confirm.