New material system (finish?); some minor bugfixes

build/engine/materials/sky/sky_hdr_hl2.mtl

build/engine/shaders/base/skybox.vs

build/engine/shaders/const.h

build/engine/shaders/default/default.ps

build/engine/shaders/default/postprocess.ps

build/engine/shaders/default/sky.ps

build/engine/shaders/default/transparent.ps

build/engine/shaders/material/gbuffer.ps

build/engine/shaders/material/illum.ps

build/engine/shaders/material/shadow.ps

build/engine/shaders/material/transparent.ps

build/engine/shaders/xmat.h

proj/sxcore/vs2013/sxcore.vcxproj

proj/sxcore/vs2013/sxcore.vcxproj.filters

proj/sxmtrl/vs2013/sxmtrl.vcxproj

proj/sxmtrl/vs2013/sxmtrl.vcxproj.filters

proj/xSpecs/vs2013/xSpecs.vcxproj

proj/xSpecs/vs2013/xSpecs.vcxproj.filters

source/ambient/SkyBox.cpp

source/ambient/SkyBox.h