Shader manager refactor; removed dead code

.gitignore

build/engine/shaders/LICENSE

build/engine/shaders/const.h

build/engine/shaders/gdefines.h

build/engine/shaders/gi/gi_cubes.gs

build/engine/shaders/gi/gi_cubes.ps

build/engine/shaders/gi/gi_cubes.vs

build/engine/shaders/gi/gi_inject.gs

build/engine/shaders/gi/gi_inject.ps

build/engine/shaders/gi/gi_inject.vs

build/engine/shaders/gi/gi_propagation.cs

build/engine/shaders/gui/gui_main.ps

build/engine/shaders/gui/gui_main.vs

build/engine/shaders/gui/gui_main_textransform.vs

build/engine/shaders/gui/gui_simple.ps

build/engine/shaders/gui/gui_simple.vs

build/engine/shaders/mtrl.h

build/engine/shaders/mtrlgeom/mtrlgeom_base.ps

build/engine/shaders/mtrlgeom/mtrlgeom_base.vs

build/engine/shaders/mtrlgeom/mtrlgeom_mr.ps