Change of API: move setting the EGL context back to the APP.
Simplify setting up DistortedScreen.
It now automatically chooses OpenGL ES 2.0 and GLSL 100 or OpenGL ES 3.0 and GLSL 300.
Postprocessing effects will not work on OpenGL ES 2.0 contexts.
Try using OpenGL ES 3.0 everywhere (but if device does not support it, try creating 2.0 context - this is important because of the emulator!)
New 'Blur' App. Actual BLUR effect, of course, does not work.