Add BranchingRenderingPipeline.
Add logging in BranchingRenderingPipeline.
Add friendly toString() to BranchingRenderingPipeline.
Log the representation of branched-to pipe.
Trivial : code style : @Mock on line with declaration.
Merge pull request #433 from apetro/UP-4259

UP-4259 : Add BranchingRenderingPipeline.