Ported from JVET-TuC with small improvements on certificate handling

Changed parameter names as suggested to upscaledOutputWidth/Height + fixed conflict with SPS conformance window. Also added the functionality to the encoder (for the reconstructed output).

Explicit specification of inter-layer reference pictures, using a layer-specific GOP structure, with 0.x syntax (0=same POC, x=reference layer).
When ExplicitILRP is true, AllowablePredDirection should not be used or left to default values (all zero), and inter-layer reference pictures are no longer inserted automatically.