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_settings.cpp

@@ -23,7 +23,7 @@ namespace BlackCore
             return contextSettings;
         }
         case CRuntimeConfig::Remote:
-            return new BlackCore::CContextSettingsProxy(BlackCore::CDBusServer::ServiceName, conn, mode, parent);
+            return new BlackCore::CContextSettingsProxy(BlackCore::CDBusServer::ServiceName(), conn, mode, parent);
         default:
             qFatal("Always initialize a settings context");
             return nullptr;