[gtk] (7 commits) Non-fast-forward update to branch wip/baedert/css-values

[Timm Bäder <baedert src gnome org>]

The branch 'wip/baedert/css-values' 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:

  f4b4b8d... css: Move border-width special cases out of GtkCssDimension
  333d8c6... testsuite: Update css color output
  c15f44f... cssvalue: Add is_computed flag
  d617388... cssvalue: Don't call compute() for already computed css val
  b8bb14d... css: Set the is_computed flag for more values
  8dcd99c... cssimage: Add is_computed vfunc

Commits added to the branch:

  c687f48... css: Move border-width special cases out of GtkCssDimension
  6b6f085... testsuite: Update css color output
  a3a71c1... cssvalue: Add is_computed flag
  ab78c19... cssvalue: Don't call compute() for already computed css val
  ab868a3... css: Set the is_computed flag for more values
  c2e680f... cssimage: Add is_computed vfunc
  d3ad970... csscolorvalue: check for singletons in new_literal