Add shutdown path for audio layer. Add basic event loop after setting up groove objects. Fix race condition bug by not setting path first.

src/main.cpp

@@ -19,6 +19,7 @@ int main ( int argc, char** argv )
         {
             GroovePlayerMgr::getInstance();
             int sig = Wt::WServer::waitForShutdown(argv[0]);
+            GroovePlayerMgr::getInstance()->shutdown();
             server.stop();
         }
         return 0;