Magic Cube

Fix marking objects as free.

Merge remote-tracking branch 'origin/master'

1. Conflicts:
2. src/main/java/org/distorted/objects/RubikObjectList.java

Fix marking objects as free.

Fix marking objects as free.

Bugfix: properly display number of stars on new installs.

fix showing the number of stars on app startup.

Stars: introductory dialog explaining the concept of stars.

Stars Overlay: fix the 'negative numbers of new stars' mode.

Stars Overlay: implement zero and negative numbers of new stars.

Minor.