RLS — (C++-PSM) Methods shall better send return codes as exceptions

As in most C++ implementations, it is better if methods will return
the return codes (Returncode_t) as exceptions.

All the class methods (functions) in beta1 specification’s C++ PSM were
returning Returncode_t value. Thus, the attributes marked as ‘out’ were handled
as by-reference arguments that were normally implemented by pointer passing.
Besides the C++ style pointed out in the summary, passing pointers are not a
good manner for effective development. Thus, we will change C++ PSM
definitions so that methods will use exceptions for passing return codes. The ‘out’
attributes will be passed as return values whenever possible.