Originally from build #28

Changes

1. JOGL2 OpenGL ES 2 demo to expose and learn what the RAW OpenGL ES 2 API looks like. (details / cgit)
2. RawGL2ES2demo: Mention JOGL probing of system installed libGL and libEGL. (details / cgit)
3. RawGL2ES2demo: make shaders Mesa X11 GL compatible. (details / cgit)
4. Adapt to JOGL's ShaderUtil API changes commit 62e5686fb583ad991d5811baf242d40d21952e27 (details / cgit)