Distorted Android

Bugfixes as a result of the Samsung Galaxy J4+ investigation:

1) By default, switch off transform feedback in the main program.
Create a new API 'needTransformFeedback()' to call if someone still needs TF in the main program.
2) lower the default max number of vertex effects to 30....

More support for using the library from more than one activity

1) Beginnings of support for using the library from more than one activity
2) rename DistortedLibrary.onCreate() to onSurfaceCreated()
3) (rubik) add Cambodia's flag.

Rename Meshes.

We need to pause an Activity in the following way:

1) Activity.onPause()
2) View.onPause()
3) Library.onPause()

otherwise sometimes there are artifacts when pausing!

Only compile the Full, Normal & OIT programs when they are actually needed.

1) Cube: convert it to the latest library. Main difference: objects are rendered better, individual cubits have rounded corners.
2) Examples: some adjustments to MeshJoin & Predeform
3) Library: fix a bug in main_vertex_shader's 'degree' function, which didn't work proprely in case of a vertex which was exactly at the center (i.e. vector PS was zero)

In library: allow a mixture of a deep and shallow copy of a Mesh ( mVertAttribs1 might be copied deeply or shallowly, mVertAttribs2 are always copied deeeply).
Port RubikCube to the new library.

Bugfix for Predeform app.

1 more fix for the Predefrom app and preapplying Vertex Effects to a 1-component Mesh works :)