– add dummy textures so that we can run the renderer before textures were loaded
– implement removing models (and their textures)
– keep track of the occurences of textures and do not overwrite them if they have the same id (do not bleed handles)
– attributes for certain function in the renderer (fix clion warnings)
Similar to the ModelManager, the TextureManager is also having the concept of dummy data to make sure to never crash, even if not fully initialised.
Furthermore it is now possible to fully remove models again, releasing the resources of models/textures if no instance of this type of model/texture no longer exists.