[glibmm] (3 commits) Non-fast-forward update to branch wip/dboles/Binding-Issue#62

[Daniel Boles <dboles src gnome org>]

The branch 'wip/dboles/Binding-Issue#62' 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:

  da82c37... Binding: Clarify need to hold ref, poss empty objs
  4b6b066... Binding: Add set_manage() to not require a RefPtr

Commits added to the branch:

  bacd92c... Binding: Test that unbind() stops props syncing
  8691675... Binding: Clarify need to hold ref, poss empty objs
  6c08aa6... Binding: Add set_manage() to not require a RefPtr