[mutter] (2 commits) Non-fast-forward update to branch wip/carlosg/no-event-source

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/no-event-source' 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:

  819608c... clutter: Drop clutter_event_[gs]et_source()
  9a59a4d... clutter: Remove "source" event union fields

Commits added to the branch:

  f557e12... clutter: Rewrite clutter_event_[gs]et_source()
  77ef52e... clutter: Remove "source" event union fields