refs #335, improved audio setup

* changed volume methods from QList<qint32> to qint32 (DBus compliance)
* methods for changed devices
* command parser for audio
* volume display in status bar (pseudo mute)

src/blackcore/context_audio_proxy.h

@@ -122,6 +122,10 @@ namespace BlackCore
 
         //! \copydoc IContextAudio::enableAudioLoopback()
         virtual void enableAudioLoopback(bool enable = true) override;
+
+        //! \copydoc IContextOwnAircraft::parseCommandLine
+        virtual bool parseCommandLine(const QString &commandLine) override;
+
     };
 }