[gtk] (4 commits) Non-fast-forward update to branch css-style-split

[Matthias Clasen <matthiasc src gnome org>]

The branch 'css-style-split' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  1a4d9ca... css: Split style into groups
  210ee55... Add accounting for styles
  c6e4a77... Add some checking for the group splitup

Commits added to the branch:

  3cdde3f... css: Don't lose inset when computing shadows (*)
  9d38806... css: Split style into groups
  c30befe... Add accounting for styles
  0ff6176... Add some checking for the group splitup

(*) This commit already existed in another branch; no separate mail sent