Changed voice context so it can play SELCAL tones. This makes sense, as I can

use the device information of this context. Sound shall be played on the
same computer as the voice.

* Adjusted .pro file
* Methods for SELCAL in context
* New XML file (DBus)
* changed the place where I can obtain the current in/output device

src/blackcore/context_voice.h

@@ -146,10 +146,14 @@ namespace BlackCore
          */
         virtual bool isMuted() const;
 
+        /*!
+         * \brief Play selcal tone
+         * \param selcal
+         */
+        virtual void playSelcalTone(const BlackMisc::Aviation::CSelcal &selcal) const;
+
     private:
         CVoiceVatlib *m_voice; //!< underlying voice lib
-        BlackMisc::Voice::CAudioDevice m_currentInputDevice; //!< input device
-        BlackMisc::Voice::CAudioDevice m_currentOutputDevice; //!< current output device
     };
 }