Magic Cube

Preparation for unification of scrambling. Scrambling of all objects will be done by a generic funtion, only fed a certain data structure by the objects. The data structure is going to be the ScrambleStateGraph - a directed state graph of all states we can come across while scrambling....

Important step towards making the implementation of an individual puzzle code-free (i.e. data-only): move the 'MeshBase[] mMeshes' variable from the individual classes to the parent TwistyObject.

Introduce ObjectShape - a class encapsulating a shape of a Cubit.
Make the Megaminx cubit creation a bit more standard.

Convert the Ivy corner cubit to the new, 'universal' cubit creation method.

This forces deep changes to 'createRoundSolid' and the underlying 'MeshPolygon' class to make them support arbitrary Polygon 'centers of face convexity'.

Reason: the faces of this cubit are concave and such default 'center of face convexity' (which by default used to be (0,0)) turned to lie outside the face - which produces strange visual artifacts.

Standarize drawing stickers of a twisty puzzle. From now on, there's no 'sticker drawing' code in the individual classes, only some constants.

Convert the last 'special' case, the Rex edge sticker, to the generic sticker mechanism.

New sticker mechanism: improvements for concave stickers.

Convert the Rex corner sticker to the new mechanism.

Remove debugging.

Generalize FactorySticker - make it possible to draw stickers whose sides are curved.
Convert the Ivy to use this new functionality.