Distorted Android

Add DistortedGridFactory to share Grids among same-shaped DistortedObjects.

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

some improvements for the way we test DistortedObjects.

fix fragment effects :)

remove the 'Color' vertex attribute.

switch precision to low in fragment shader

Make the 'deform' effect continuous when 'center' point passes through (0,0) i.e. middle of the Object.

Avoid a crash on exiting MessageSender

fix in vertex shader

Bugfix in vertex shader (vertices were shot into outer space if P==S, i.e. if center point was exactly equal to the vertex being computed)