Support glProgramUniform*() calls from OpenGL ES 3.1.

The code both supports new features *and* is shorter, yay!
Mark also all GL 4.5 extensions as supported if GL 4.5 is supported.

Oh god, it got to the point where I should write an HOWTO *for myself*.
Preparation for ARB_direct_state_access GL 4.5 feature.

Renamed all EXT_direct_state_access implementations to reflect the fact
that these aren't using the ARB extension.
ARB_direct_state_access support for creating textures.
ARB_direct_state_access support for creating buffers.
ARB_direct_state_access support for creating framebuffers.
ARB_direct_state_access support for creating renderbuffers.
ARB_direct_state_access support for creating meshes.
doc++