pothos-library: begin work on signal emitter support
pothos-library: implement signals and slots api on top of ports
pothos-blocks: signal+slots demo unit test
pothos-library: added registerSlot API call + comments
pothos-library: added class registrations for signals/slots setup
pothos-python: signals and slots support + unit test
pothos-library: emit signal args now takes a vector of objects
Merge branch 'signals_and_slots'