Quick Loader (Sokoban)

0.3.13.23:
- added a button to join beta on Google Play;
- added loader animation;
- added showing level goal;
- added showing the best level result and how many players have completed the level;
- fixed bugs.
0.3.8.18:
- added showing completed/total levels;
- added user level rating;
- added an animation on loading button;
- fixed loading levels online.
0.3.5.15:
- updated tutorial icon;
- fixed a bug, when backstep, the last moved box was moved, even if it was no longer nearby.