Added context information to Hamlib interface exception messages.

Enhanced TransceiverBase  error exception  type to allow  for language
translatable messages.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4033 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

DXLabSuiteCommanderTransceiver.hpp

@@ -21,6 +21,8 @@ class QTcpSocket;
 class DXLabSuiteCommanderTransceiver final
   : public PollingTransceiver
 {
+  Q_OBJECT;                     // for translation context
+
 public:
   static void register_transceivers (TransceiverFactory::Transceivers *, int id);