Distorted Android

Beginnings of support for DistortedEffects.drawPrivFeedback()

This commit (and reading the OpenGL ES 3.0 spec) pretty conclusively proves that, sadly, Nexus 4's Transform Feedback implementation is incomplete (doesn't work with GL_TRIANGLES primitiveMode)

Progress with TransferFeedback app - introduce two modes: USEPOINTS 'true' or 'false'.

On Nexus5X, it works with 'true' and 'false'. On Nexus 4, it works with 'true', but returns GL_INVALID_OPERATION with 'false'.

This version appears to be fully working on Nexus 5X (it transfers back all the vertices and, if there are no vertex effects, the vertices transferred back are identical to the ones passed).

This however crashes with GL_INVALID_OPERATION during glDrawArrays() when run on Nexus 4.

Progress with Transform Feedback.

Progress with VBOs - this time abstract out a new class, DistortedObject - i.e. everything that uploads something to GPU and thus needs to be auto re-created upon loss of the context.

Preparation for Transfer Feedback: Convert the meshes from client-side to VBOs.

Minimize differences from master branch.

Progress with moving the Transform Feedback functionality from the APP to the library.

Remember the URL with Transform Feedback example.