[glibmm] (12 commits) Non-fast-forward update to branch wip/dboles/SettingsSchemaSource-Issue#19

[Daniel Boles <dboles src gnome org>]

The branch 'wip/dboles/SettingsSchemaSource-Issue#19' 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:

  875dacf... SettingsSchemaSource: Implement list_schemas()
  43f4574... SettingsSchemaSource: Wrap new_from_directory()

Commits added to the branch:

  c66533c... fix ustring::insert(iterator, In, In) (*)
  65ddb67... Glib::Binding: get_source() and get_target() return ObjectB (*)
  89cfdff... Merge branch 'fix-ustring-insert' into 'master' (*)
  e1d1f6d... Glib: Adding static check for template parameter (*)
  d3f7d61... Avoid unnecessary conversions between std::string and Glib: (*)
  18f0ca8... Update value_custom.h (*)
  a1bdfdb... Merge branch 'wip/gvalue_assert' into 'master' (*)
  9015d94... Glib: Replace StringView with StdStringView and UStringView (*)
  c84f13c... Glib::Regex: Use UStringView (*)
  a755523... Merge branch 'fix-issue-66' into 'master' (*)
  bf11662... SettingsSchemaSource: Implement list_schemas()
  3edb73a... SettingsSchemaSource: Wrap new_from_directory()

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