Distorted Android

Only show the OpenGL Error dialog when the underlying hardwarre does not support OpenGL ES 3.0.

Preparation for saving/reading Meshes to/from a file.

Progress making it possible to apply Vertex Effects only to some Components of a Mesh.

Report a Crashlytics non-fatal if we fail to compile some shaders.

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.

Fix VertexEffectRotate.
'MeshJoin' app now back it its functionality from 'master'

Some progress with 'MeshJoin' app.

Change 'tag' to a more appropriate name - 'association'.

Introduce 'tags' (soon to be renamed to 'associations') to Mesh and VertexEffect.
A 'tag' is a way to associate a Vertex Effect only to a subgroup of a given Mesh's vertices (more precisely, only to an arbitrary subset of its Components)