refs #382, reviewed audio context handling

* only init QDbusServer for P2P
* changed init order of contexts in runtime
* use "fake" signal to call setComVoiceRooms (remote in GUI)
* added slot to change voice room callsign
* used "org.swift" instead of "net.vatim" (just style)
* used const QString for serviceName
* added correct copyright header (just style)

src/blackcore/context_ownaircraft.cpp

@@ -18,7 +18,7 @@ namespace BlackCore
         case CRuntimeConfig::LocalInDbusServer:
             return (new CContextOwnAircraft(mode, parent))->registerWithDBus(server);
         case CRuntimeConfig::Remote:
-            return new BlackCore::CContextOwnAircraftProxy(BlackCore::CDBusServer::ServiceName, conn, mode, parent);
+            return new BlackCore::CContextOwnAircraftProxy(BlackCore::CDBusServer::ServiceName(), conn, mode, parent);
         default:
             qFatal("Always initialize an ownAircraft context");
             return nullptr;