Prepare the 'objectlib' package to be separated into a library module
Refactoring: split the 'objects' package into two, 'objects' and 'objectlib'.The point: we're going to need to move the 'objectlib' stuff into its own library module, and that's because we're going to create a new app module which needs access to it.
Remove class referencees from ObjectList.
Add Mirror Cube 2x2 and 3x3.
Move the TwistyObject.retCubePosition() to the solver.
Abstract the part that controls the 'Locked' and 'Back Moves' buttons from the two activities: the main one and the tutorial one.This code had been duplicated there.
Cube Control: step 2.
Rename 'state' to 'screen'