Distorted Android

Refactor the 'Generic' app.

Avoid a potential crash on exit

Before we start rendering, effects can always be added.

Bugfix: default, MAX region cannot be of Float.MAX_VALUE radius - then in the shader we can have an overflow. Make it 1000000 in radius.

1) new 'Rubik' app (skeleton)
2) MeshCubes: add support for custom texture mappings on each side (Rubik needs that!)

Some improvements to the Wind app - still does not look very realistic though :(

Correct Distort.

Make Distort truly 3D.

Fixes for some stuff discovered while making the Distort effect fully 3D:

- make MeshSphere's normal lengths be 1 (used to be 0.5)
- make the Effect3D app display precise values of the Center and Region vars.

Relax requirements on when we can call DistortedEffects.setMax().

Before this change one had to call it before creation of shaders and before any of the DistortedEffects classes got created.
This commit removes the second requirement so now with setMax it's just like with enabling effects: it's best done in onSurfaceCreated.