Add Rendergroup

assets/shaders/Image.frag

assets/shaders/Image.vert

source/engine/graphics/back/geometry/Geometry.hpp

source/engine/graphics/back/geometry/Geometry.tpp

source/engine/graphics/back/textures/TextureBuffer.cpp

source/engine/graphics/back/textures/TextureBuffer.hpp

source/engine/graphics/front/geometry/FlatGeometry.cpp

source/engine/graphics/front/geometry/FlatGeometry.hpp

source/engine/graphics/front/group/DrawGroup.hpp

source/engine/graphics/front/group/ImageGroup.cpp

source/engine/graphics/front/group/ImageGroup.hpp

source/engine/graphics/front/object/Image.cpp

source/engine/graphics/front/object/Image.hpp

source/main.cpp

source/main.cpp.old