Distorted Android

First attempt at the 'Mirror' app.

Fix Lint warnings, correct a lot of comments, adjust EffectListener interface.

Fix a lot of Lint warnings in the apps.

Again change of API. Now instead of the 'DistortedEffects.draw() and DistortedTree.draw()' we have 'DistortedFramebuffer.renderTo()'

Change of names.

Change in the API: we always have to create a DistortedFramebuffer to render to.

onPause(): fix the Save app. All apps should behave correctly now.

onPause(): fix StarWars

Some improvements for StarWars's behaviour after onPause(), but it doesn't really work yet.

Remaining 'onPause-buggy' apps: StarWars, Save.

Fix 'FBO' and 'MovingEffects's behaviour after onPause().