libsigc++: New API in libsigc++ 2.8
- Member sigc::signal_base::connect (slot_base&& slot_)
- Member sigc::signal_base::insert (iterator_type i, slot_base&& slot_)
- Member sigc::signal_with_accumulator< T_return, T_accumulator, T_arg >::connect (slot_type&& slot_)