Support multiple pointers in ClutterDragAction.
Support multiple pointers in ClutterDragAction.

https://bugzilla.gnome.org/show_bug.cgi?id=653066

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