[gtk] (7 commits) Non-fast-forward update to branch matthiasc/for-master

[Matthias Clasen <matthiasc src gnome org>]

The branch 'matthiasc/for-master' 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:

  92ddc7a... cssshadowvalue: Add gtk_css_shadow_value_pop_snapshot
  adadf7d... cssshadowvalue: Add a parsing function
  c4450ce... cssshadowvalue: Add a 'filter mode'
  dfecca4... cssfiltervalue: Implement drop-shadows
  efb6789... cssfiltervalue: Fix blur filter interpretation
  0acc728... cssfiltervalue: Reject invalid filters
  1a6c747... Add tests for the css filter property

Commits added to the branch:

  49ec650... cssshadowvalue: Add gtk_css_shadow_value_pop_snapshot
  3e150d0... cssshadowvalue: Add a parsing function
  069516d... cssshadowvalue: Add a 'filter mode'
  18b0279... cssfiltervalue: Implement drop-shadows
  5527b1a... cssfiltervalue: Fix blur filter interpretation
  cd99e91... cssfiltervalue: Reject invalid filters
  336fd92... Add tests for the css filter property