Distorted Android

Add a glGetError() call to the main render loop.

Minor.

Add info about FPS.

Progress replacing the enum ObjetType with the class RubikObjectList.

Adjust ShapeChanging so that it can handle concave cubit faces.
Now it is working also in case of the Ivy corner cubits.

Float vertices - scratchbook

Bugfix.

Add to MeshPolygon a special modee to create a 2-band polygon with dense corners (needed to reduce number of vertices in side faces of the TwisttyPuzzle cubits)

Add testing of MeshPolygon to the MeshFile app.

Major change: separate the notion of a TwistyObject and its Node. Now,

1) the Node stays when we change objects (this makes transitions faster)
2) it's possible to just create an Object without adding it to the Screen (now app needs to explicitly create the Node and add it to its Screen itself)