Distorted Android

A little progress making the postprocessing buffers static.

Introduce possibility that an OutputSurface is backed up by a larger texture than necessary and the 'cloneSize()' method.

Improve Blur (boundaries should be more white than black)

New 'Triblur' testapp.

Shows that the Blur effect doesn't fully work (probably it is the 'blitWithDepth' function which needs to be corrected)

SSBO: now we have a more-or-less correct running average of the count of transparent fragments over the last few frames.

SSBO: correct various things.

SSBO: zero out the per-surface transparent fragment counter only when setting the surface as output for the first time in the frame.

SSBO: handle the fact that we might run out of space in our SSBO if we keep creating new Surfaces.

SSBO: counting of transparent fragments more or less works now. Still the counters are zeroed out in the wrong place - every time we start rendering something to a given Surface, rather than once per frame.

SSBO: more and more works...