Distorted Android

Improve locking in DistortedObject.
DistortedMaster: slaves can be NULL !

Many things.

1) make the Dynamic.setDuration() able to be called AFTER the Dynamic has already been run. (and rename it to 'makeRunNowFor()' )
2) remove the automatic removal of zero Effects from EffectQueues.
3) adjust several Apps to cope with 2)
4) add post-rotation to Rubik (still not finished)

Add correct normal vectors to the PINCH effect. The effect is now fully 3D.

Make the 'PINCH' effect fully 3D (define its acting line in terms of (latitude,longitude) angle pair).

Still, something is not fully working in the Earth app with the effect - investigate.

Add (simplified, approximated) shading to the Sink effect, i.e. move the normal vectors.

Remove unused imports.

Finish the Rubik app.

Refactor the 'Generic' app.

Avoid a potential crash on exit

Before we start rendering, effects can always be added.