Doomsday Engine

Merge branch 'master' into revise-texture-animation

Conflicts:
doomsday/engine/include/gl/gl_main.h
doomsday/engine/include/map/surface.h
doomsday/engine/include/render/sprite.h
doomsday/engine/include/resource/material.h
doomsday/engine/include/resource/materials.h
doomsday/engine/include/resource/materialvariant.h
doomsday/engine/src/def_data.cpp
doomsday/engine/src/map/p_dmu.cpp
doomsday/engine/src/map/surface.cpp
doomsday/engine/src/render/rend_decor.cpp
doomsday/engine/src/render/rend_main.cpp
doomsday/engine/src/resource/material.cpp
doomsday/engine/src/resource/materials.cpp