config: port to yamlcpp

daemon/configure.ac

daemon/src/Makefile.am

daemon/src/account.cpp

daemon/src/account.h

daemon/src/config/Makefile.am

daemon/src/config/serializable.h

daemon/src/config/sfl_config.cpp

daemon/src/config/sfl_config.h

daemon/src/config/yamlemitter.cpp

daemon/src/config/yamlemitter.h

daemon/src/config/yamlnode.cpp

daemon/src/config/yamlnode.h

daemon/src/config/yamlparser.cpp

daemon/src/config/yamlparser.h

daemon/src/global.h

daemon/src/history/historynamecache.cpp

daemon/src/history/historynamecache.h

daemon/src/iax/iaxaccount.cpp

daemon/src/iax/iaxaccount.h

daemon/src/iax/iaxvoiplink.cpp