[feature] Copy constructor for IRenderTarget

[yogwoggf]

Is your feature request related to a problem? Please describe.
My post-processing VisTrace extension relies a lot on rendertargets, so it'd be beneficial for me to be able to copy IRenderTargets around.

Describe the solution you'd like
I want a copy constructor to be added to IRenderTarget which would

Describe alternatives you've considered
There is no (good) alternative to this.

[yogwoggf]

Just some quick researching before implementing.. virtual copy constructors don't exist

[Derpius]

The interface class shouldn’t have a copy constructor, the derived class should…