Add a warning when ClutterInterval can't compute progress
Add a warning when ClutterInterval can't compute progress

This is really useful when trying to animate GTypes that haven't
registered any progress function. Instead of silently not working it
will warn the developer.

http://bugzilla.openedhand.com/show_bug.cgi?id=1845

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