Fix tone by Jerome Oufella

ChangeLog

src/audio/audiolayer.cpp

src/audio/ringbuffer.cpp

src/audio/tonegenerator.cpp

src/gui/qt/qtGUImainwindow.cpp

src/manager.cpp

src/sipvoiplink.cpp

utilspp/lifetime_default.hpp

utilspp/lifetime_with_longevity.hpp

utilspp/lifetime_with_longevity.inl

utilspp/null_type.hpp

utilspp/private_members.hpp

utilspp/private_members.inl

utilspp/threading_single.hpp