Blender Git Loki

BGE: Fix T37074: GLSL max texture units limit

Actually for the the amount of GLSL textures units is limited by the amount of multitexture units (GL_MAX_TEXTURE_UNITS_ARB).
Most of the Nvidia graphic cards supports only 4 multitexture units, so Nvidia users can not use more then 4 GLSL textures for a custom shader.
This patch removes this limitation by using GL_MAX_TEXTURE_IMAGE_UNITS_ARB if GLSL is supported, but still limit the amount to the maximum texture limit of 8.

Reviewers: lordloki, agoose77, danielstokes, panzergame, sybren, moguri

Reviewed By: panzergame, sybren, moguri

Projects: #game_engine, #game_rendering

Maniphest Tasks: T37074

Differential Revision: https://developer.blender.org/D1389