glibmm: New API in glibmm 2.20

# New API in glibmm 2.20

Member Gio::AppInfo::can_delete () const

Member Gio::AppInfo::do_delete ()

Member Gio::AppInfo::get_commandline () const

Member Gio::AppInfo::reset_type_associations (const std::string& content_type)

Member Gio::content_type_from_mime_type (const Glib::ustring& mime_type)

Member Gio::Drive::signal_changed ()

Member Gio::Drive::signal_disconnected ()

Member Gio::Drive::signal_eject_button ()

Class Gio::Emblem

Class Gio::EmblemedIcon

Member Gio::Icon::to_string () const

Class Gio::MemoryOutputStream

Member Gio::Mount::is_shadowed () const

Member Gio::Mount::shadow ()

Member Gio::Mount::unshadow ()

Member Gio::UnixInputStream::get_close_fd () const

Member Gio::UnixInputStream::get_fd () const

Member Gio::UnixInputStream::set_close_fd (bool close_fd=true)

Member Gio::UnixOutputStream::get_close_fd () const

Member Gio::UnixOutputStream::get_fd () const

Member Gio::UnixOutputStream::set_close_fd (bool close_fd=true)