Add methods to read received callsigns from AFV

ref T729

src/blackcore/afv/audio/receiversampleprovider.cpp

@@ -123,12 +123,13 @@ namespace BlackCore
                         }
                     }
 
+                    m_receivingCallsigns = receivingCallsigns.join(',');
                     TransceiverReceivingCallsignsChangedArgs args = { m_id, receivingCallsigns };
                     emit receivingCallsignsChanged(args);
                 }
                 lastNumberOfInUseInputs = numberOfInUseInputs;
 
-//    return volume.Read(buffer, offset, count);
+//            return volume.Read(buffer, offset, count);
                 return m_mixer->readSamples(samples, count);
             }
 
@@ -199,6 +200,11 @@ namespace BlackCore
                 }
             }
 
+            QString ReceiverSampleProvider::getReceivingCallsigns() const
+            {
+                return m_receivingCallsigns;
+            }
+
 
         } // ns
     } // ns