(PCP-463) Unit test for storing/rethrowing Monitor Task exceptions
(PCP-463) Unit test for storing/rethrowing Monitor Task exceptions

Adding 2 unit tests for ensuring that exceptions caught by the Monitor
Thread are stored a rethrown by the dtor and the stopMonitoring method.

puppetlabs/cpp-pcp-client,MikaelSmith/cpp-pcp-client,MikaelSmith/cpp-pcp-client,puppetlabs/cpp-pcp-client,puppetlabs/cpp-pcp-client,MikaelSmith/cpp-pcp-client,MikaelSmith/cpp-pcp-client,puppetlabs/cpp-pcp-client,MikaelSmith/cpp-pcp-client