daemon: replace SFL references by Ring in src/

src/client/callmanager.cpp

src/managerimpl.cpp

src/media/audio/audiolayer.h

src/media/audio/coreaudio/corelayer.cpp

src/media/audio/jack/jacklayer.cpp

src/media/libav_utils.cpp

src/media/libav_utils.h

src/media/media_buffer.cpp

src/media/media_decoder.cpp

src/media/media_encoder.cpp

src/media/socket_pair.cpp

src/preferences.cpp

src/ringdht/ringaccount.h

src/sip/sipaccount.h

src/sip/tlsvalidator.cpp