[docs] Add more gtk-doc annotations
[docs] Add more gtk-doc annotations

Almost reaching full documentation.

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