css: Make CSS resolving work according to spec
css: Make CSS resolving work according to spec

See inline code comments taken from
  http://dev.w3.org/csswg/css3-cascade/#cascade

This now respects the special values "inherit" and "initial" properly.
Note that those values cannot be parsed yet. This will be added in a
future commit.

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