[static analysis] Add "Include What You Use" (iwyu)

Makefile

apps/Main.cpp

apps/WorkerSleepExample.cpp

emper/BinaryPrivateSemaphore.cpp

emper/BinaryPrivateSemaphore.hpp

emper/Common.cpp

emper/Common.hpp

emper/Context.hpp

emper/ContextManager.cpp

emper/ContextManager.hpp

emper/CountingPrivateSemaphore.cpp

emper/CountingPrivateSemaphore.hpp

emper/Debug.cpp

emper/Debug.hpp

emper/Dispatcher.cpp

emper/Dispatcher.hpp

emper/Fiber.cpp

emper/Fiber.hpp

emper/FiberManager.cpp

emper/FiberManager.hpp