Distorted Android

Minor stuff - comments.

Some progress with Fragment3D app - doesn't compile yet!

Revert the Cubes App.

Add DistortedGridFactory to share Grids among same-shaped DistortedObjects.

revert latest changes to the fragment shader.
small things in DistortedObjects.

remove the 'Color' vertex attribute.

Avoid a crash on exiting MessageSender

Minor: deal with IntelliJ warnings

minor

Important bugfix in the vertex shader: there was division by 0 in case Center point was on the edge of the Object, resulting in some vertices being shot into outer space.