Distorted Android

Fix issue with Blur / Multiblur apps

1. Make it possible to enable/disable DEPTH test when rendering to a Screen
2. Using this, remove the 'Root' Node from StarWars.

A lot of different fixes.

A lot of issues still there:

1) if we only render part of the tree, tree isomorphism will sometimes not work correctly
2) when we change Effects that are inside Trees mid-render, even if we detach() the affected parts of the Tree first, for the last frame the new Effects will be used...

New, cleaner way to create/destroy DistortedSurfaces.

Serious regression in StarWars (crashes!). Looks like the Node's internal FBO is being deleted and not re-created in time.

New, cleaner way to create/destroy DistortedSurfaces.

Serious regression in StarWars (crashes!). Looks like the Node's internal FBO is being deleted and not re-created in time.

Change the the render() API!

THis introduces some regressions with the Effects3D app.

Preparation for change of the render API.

Minor

Simplify yesterday's refactoring.

Major: change of API.

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