[clutter-id-pool] Also warn if the ID refers to a deleted actor
[clutter-id-pool] Also warn if the ID refers to a deleted actor

We should also warn if the glReadPixels happens to generate an ID that
is within the range of the ID array but no longer points to an
existing actor.

jigpu/clutter,heysion/clutter-clone,Distrotech/clutter,rkudiyarov/clutter_osx,djdeath/clutter-multithreaded,GNOME/clutter,rkudiyarov/clutter_osx,heysion/clutter-clone,djdeath/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,collects/clutter,ebassi/clutter,nobled/clutter,jigpu/clutter,heysion/clutter-clone,GNOME/clutter,ebassi/clutter,dlespiau/clutter,collects/clutter,jigpu/clutter,djdeath/clutter-android,collects/clutter,GNOME/clutter,spatulasnout/clutter,rkudiyarov/clutter_osx,collects/clutter,Distrotech/clutter,ebassi/clutter,rkudiyarov/clutter_osx,Distrotech/clutter,GNOME/clutter,spatulasnout/clutter,dlespiau/clutter,djdeath/clutter,Distrotech/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,dlespiau/clutter,djdeath/clutter,nobled/clutter,jigpu/clutter,Distrotech/clutter,djdeath/clutter-multithreaded,djdeath/clutter-android,djdeath/clutter-multithreaded,nobled/clutter,spatulasnout/clutter,ebassi/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,jigpu/clutter,jigpu/clutter,heysion/clutter-clone,kerrickstaley/clutter-vala,collects/clutter,djdeath/clutter,heysion/clutter-clone,djdeath/clutter,djdeath/clutter,Distrotech/clutter,djdeath/clutter-multithreaded,spatulasnout/clutter,spatulasnout/clutter,ebassi/clutter,GNOME/clutter