Revert "model: Use guint for the n_columns field"
Revert "model: Use guint for the n_columns field"

The int storage, and the initial value of -1, is used as a guard when
subclassing ClutterListModel to allow the sub-class to call
clutter_model_set_names() and clutter_model_set_types().

This reverts commit c274118a8f7ed18e5bc703e614a9ea0a7cdb553c.

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