Big rendering refactor: fully modern OpenGL support (3.3 core profile), mobile OpenGL

[DP News-Robot]

We have made a few significant refactors of our low-level OpenGL(ES) code, to support better both modern GPUs, ancient GPUs and mobile GPUs. Everybody wins! ? Modern GPUs We have now much better support of new OpenGL features. If we have shaders, we know we have shaders from “core”, and we initialize them with the …