Ability to ignore material shader for given pass

build/engine/shaders/terrax/geom2d.ps

build/engine/shaders/terrax/terrax_colored.ps

build/engine/shaders/terrax/terrax_textured.ps

source/anim/Renderable.cpp

source/mtrl/MaterialSystem.cpp

source/mtrl/MaterialSystem.h

source/terrax/terrax.cpp