Mutex: return int from Mutex::unlock()
Mutex: implement POSIX error handling in Mutex::unlock()
Mutex: keep number of recursive locks in the object
Mutex: rework Mutex::lock() structure, so that it stands out that
locking an unlocked mutex is a very simple operation
Mutex: rework Mutex::tryLock() structure, so that it stands out that
locking an unlocked mutex is a very simple operation
Mutex: rework Mutex::tryLockUntil() structure, so that it stands out
that locking an unlocked mutex is a very simple operation
Mutex: add Mutex::tryLockInternal()
Mutex: implement Mutex::tryLock() with Mutex::tryLockInternal()
Mutex: implement main part of Mutex::lock() with
Mutex::tryLockInternal()
Mutex: implement main part of Mutex::tryLockUntil() with
Mutex::tryLockInternal()
Mutex: implement handling of Recursive type of Mutex in Mutex::unlock()
and Mutex::tryLockInternal()
test: add waitForNextTick() helper function
test: add MutexOperationsTestCase
test: add MutexOperationsTestCase to list of executed test cases