Issue #1986334 by David_Rothstein, grndlvl, EclipseGc, ruloweb, vilepickle,...

Issue #1986334 by David_Rothstein, grndlvl, EclipseGc, ruloweb, vilepickle, heddn, MiroslavBanov, brantwynn, mairi, danieltome, azinck, DamienMcKenna, slucero: Optionally allow each FPP pane to be referenced by revision ID, allowing for editorial workflows when used with Panelizer.