Let there be light

And there was light!
For now there is no scene graph or property implementation, all lights are added in painter.cpp, check that out to see how you can add lights.
i would define a ```const int MAX_NUM_LIGHTS``` and if glow is integrated later on, this should be set via string replacement. For arbitrary many lights we could instead use float textures that have the required information encoded (textures, since shader storrage buffers are no option for cgsee yet - ogl 4.3)