Qutexes: Implement them and supporting classes

Implements: LockSet, SerializedAsynchronousContinuation,
	LockerAndInvoker, LockerAndInvokerBase, Qutex.

Very big leap in functionality here. See qutexes.md for
an explanation of what we've done.

smocore/lockerAndInvokerBase.cpp

@@ -0,0 +1,5 @@
+#include <lockerAndInvokerBase.h>
+
+namespace smo {
+
+} // namespace smo