merged with upstream dev

CMakeLists.txt

assets/scenes/_default.yml

assets/scenes/demo1.yml

assets/shaders/base.glsl

assets/shaders/subsurfaceScatter.glsl

include/overkill/EntityDirectionalLight.hpp

include/overkill/EntityPointLight.hpp

include/overkill/Scene.hpp

include/overkill/ShaderSystem.hpp

include/overkill/UniformBuffer.hpp

src/EntityCamera.cpp

src/EntityDirectionalLight.cpp

src/EntityPointLight.cpp

src/Parser.cpp

src/Scene.cpp

src/ShaderSystem.cpp

src/main.cpp

tool/export.py