[build] Install JSON headers inside the right directory
[build] Install JSON headers inside the right directory

Don't install inside the clutter-MAJOR_MINOR/ directory, but use
the API_VERSION (1.0).

Otherwise we'd have the Clutter headers for 1.x inside:

        $includedir/clutter-1.0/clutter

And the JSON-related headers inside:

        $includedir/clutter-1.<minor>/clutter

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