New API in glibmm 2.12

Member Glib::KeyFile::set_double (const Glib::ustring& group_name, const Glib::ustring& key, double value)
Member Glib::KeyFile::set_double (const Glib::ustring& key, double value)
Member Glib::OptionContext::get_description () const
Member Glib::OptionContext::get_summary () const
Member Glib::OptionContext::set_description (const Glib::ustring& description)
Member Glib::OptionContext::set_summary (const Glib::ustring& summary)
Member Glib::OptionContext::set_translation_domain (const Glib::ustring& domain)