Distorted Android

Merging blurred surfaces mostly ok now (blurred image still appears a bit shifted down for some reason)

Simplify shaders.

Make it more flexible; now it can run almost all apps on OpenGL 2.0 contexts; OpenGL 3.0 ( with GLSL 3.00) required for POSTPROCESSING.

Upgrade from GLSL 1.00 to GLSL 3.00 ES
Introduce separate BLUR1 and BLUR2 shaders, the second one marging (writing to gl_FragDepth still does not work)

Simplify BLUR shader.

Simplify drawRecursive

simplify blitPriv()

Introduce Effects.blitPriv() (faster than previous drawNoEffectsPriv)

Minor

Speed up shaders (both compilation and execution) by explicitly enabling only the needed effects.