Refactor resource scale API to be based on stage-views lists
This MR changes the resource scale API to be based on ClutterActors new stage-views list (see !1196 (merged)).
It also introduces proper support for actors like ClutterText where the allocation depends on the resource-scale, which allows getting the size and position perfect on the first frame.
Depends on !1196 (merged), !1181 (merged)
Corresponding shell MR: gnome-shell!1287 (merged)
Edited by Robert Mader