AGENT++v3.4c

[Frank Fock]

Hello AGENT++ Users,

another update of AGENT++v3.4 with a few minor fixes
was necessary. These are the changes:

* Fixed EndOfMibView exception reporting for GETBULK
  requests. It did not return the request oid in
  the exception variable binding, instead it returned
  the last found oid.

* Fixed compilation errors without _THREADS defined
  in agent++.h.

Kind regards,
Frank Fock