refs #316 Changed blackcore to use CLogMessage to emit messages.

Also changed functions which always returned CStatusMessageList containing a single CStatusMessage,
to return CStatusMessage instead for simplicity.

src/blackcore/voice.h

@@ -50,6 +50,8 @@ namespace BlackCore
         IVoice(QObject *parent = nullptr);
 
     public:
+        //! Log message category
+        static QString getMessageCategory() { return "swift.voice"; }
 
         //! Virtual destructor.
         virtual ~IVoice() {}