window: Allow theme control over window buttons
window: Allow theme control over window buttons

Add a style property to control the presence and order of
window buttons. We allow buttons at the left and right side,
they can be specified like this: icon,close:minimize,maximize.

Also, change the default button layout back to have just a close
button on the right, use icons in buttons, and set style classes
on the buttons, to allow better theming.

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