HHRfNode: private type definition.
HHRfNode: time stamp stratergy changed.

Timestamp #1: generated.
Timestamp #2: first being dispatched.
Timestamp #3: received by R (SR transmission) or by D (SD transmission).
Timestamp #4: received by D (RD transmission).
Changed Makefile.

Well, since no interface is used in this project, it's actually quite
difficult to inherit from a class, because all parent classes' this are
useless as long as no virtual table is available.
HHRftNode: complete, to be tested.