[mutter] (6 commits) Non-fast-forward update to branch wip/carlosg/axe-libsn

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/axe-libsn' 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:

  784c209... x11: Drop usage of libstartup-notification
  2a51187... core: Set timestamp in our DESKTOP_STARTUP_ID tokens

Commits added to the branch:

  ab7ef5f... core: Fix differing sequence timestamp precision expectatio (*)
  40103d6... core: Account for completed sequences in feedback updates (*)
  38ff01d... core: Add MetaStartupSequence::complete signal (*)
  3de6f7e... core: Emit MetaStartupNotification::changed on sequence com (*)
  217bd31... x11: Drop usage of libstartup-notification
  aea56b6... core: Set timestamp in our DESKTOP_STARTUP_ID tokens

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