Distorted Android

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.

Massive: make the coordinate system agree with that of OpenGL (i.e. invert the Y axis).

Make the Fragment effects truly 3D: change their 4D 'region' into a 3D 'center' (a point in 3D) and 3D 'region' (which is now a set of 3 radii defining an ellipsoid around the center)

Also corresponding changes to the applications.

Advances with the Earth app - prepare it to checking if any FRAGMENT or VERTEX effect correctly works on a Sphere mesh.

Redefine the Vertex Region from (x,y,r,unused) to (x,y,z,r). This takes into account the 'Z', which makes it possible to warp only one side of a 3D Mesh like Sphere.

Also corresponding changes in applications.

Fully move the Meshes to their own package.

Convert everythig to GLES31 (there were some GLES30 remnants)

Move all the knowledge about Vertex and Fragment effects to their respective classes.

Change of API: move setting the EGL context back to the APP.

Small API simplification.