new file:   threadsafe_lazy_init_by_std_call_once.hpp
	new file:   threadsafe_lazy_init_by_std_call_once_test.cpp
	deleted:    threadsafe_lazy_init_by_std_call_once.hpp
	deleted:    threadsafe_lazy_init_by_std_call_once_test.cpp
	modified:   README.md
added tested commented
	new file:   ch04/test_for_condition_variable.cpp