Distorted Android

Convert a few more APPs to the new resolution-independent Matrix Effects.

Fix PlainMonaLisa's Activity lifecycle (it wouldn't work after a POWER button press, i.e. after a brief time in the background - surfaceCreated is not called in this case)

Major:

1) in the Library, fix the fact that some applications (those that were creating their DistortedSurface objects outside of onSurfaceCreated or onSurfaceChanged) would not render after the activity went to background (press POWER to see that).
2) in the Apps, call the new 'Distorted.onPause()' API to fix the above problem...

New 'glClearColor' and 'glClearDepthf' APIs in OutputSurface. This fixes the 'transparency' regressions from last commit.

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

Change the the render() API!

THis introduces some regressions with the Effects3D app.

Major: change of API.

Split DFramebuffer into Framebuffer and Screen; introduce the 'DistortedInputSurface' and 'DistortedOutputSurface' interfaces.

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!)

Progress with multi-program rendering.

Rename Grid to Mesh