GtkColorChooser: Fix selection of colors
GtkColorChooser: Fix selection of colors

Prevent the new window dragging code from interfering with
selection of colors on button release, by handling button
presses we care about instead of letting them bubble up to
the window.
Partial fix for
https://bugzilla.gnome.org/show_bug.cgi?id=695493

jigpu/gtk,bratsche/gtk-,alexlarsson/gtk,ahodesuka/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,jessevdk/gtk,chergert/gtk,Lyude/gtk-,ahodesuka/gtk,Lyude/gtk-,jessevdk/gtk,Adamovskiy/gtk,Adamovskiy/gtk,alexlarsson/gtk,davidgumberg/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,ahodesuka/gtk,grubersjoe/adwaita,jadahl/gtk,Distrotech/gtk2,jessevdk/gtk,jigpu/gtk,Lyude/gtk-,jadahl/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,Sidnioulz/SandboxGtk,chergert/gtk,msteinert/gtk,grubersjoe/adwaita,Sidnioulz/SandboxGtk,Lyude/gtk-,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,Adamovskiy/gtk,Distrotech/gtk2,davidgumberg/gtk,chergert/gtk,Adamovskiy/gtk,msteinert/gtk,msteinert/gtk,jadahl/gtk,ahodesuka/gtk,bratsche/gtk-,chergert/gtk,jigpu/gtk,chergert/gtk,ahodesuka/gtk,jigpu/gtk,grubersjoe/adwaita,grubersjoe/adwaita,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,chergert/gtk,msteinert/gtk,jessevdk/gtk,Lyude/gtk-,Distrotech/gtk2,Adamovskiy/gtk,ahodesuka/gtk,grubersjoe/adwaita,Sidnioulz/SandboxGtk,jigpu/gtk,bratsche/gtk-,Adamovskiy/gtk,Adamovskiy/gtk,davidgumberg/gtk,davidgumberg/gtk,jadahl/gtk,davidgumberg/gtk,grubersjoe/adwaita,alexlarsson/gtk,Distrotech/gtk2,jessevdk/gtk,ebassi/gtk,bratsche/gtk-,ebassi/gtk,ebassi/gtk,ebassi/gtk,ebassi/gtk,Lyude/gtk-,davidgumberg/gtk,jadahl/gtk,bratsche/gtk-,Lyude/gtk-,ahodesuka/gtk,alexlarsson/gtk,Distrotech/gtk2,jadahl/gtk,bratsche/gtk-,jessevdk/gtk,msteinert/gtk,jigpu/gtk,chergert/gtk,chergert/gtk,ebassi/gtk,davidgumberg/gtk,jigpu/gtk,alexlarsson/gtk,Lyude/gtk-,jigpu/gtk,Distrotech/gtk2,jadahl/gtk,msteinert/gtk