pushnotifications: fix build without push notifications, improve travis script

tools/dhtnode.cpp

@@ -219,12 +219,6 @@ void cmd_loop(std::shared_ptr<DhtRunner>& dht, dht_params& params
 #endif //OPENDHT_PROXY_SERVER
 #if OPENDHT_PROXY_CLIENT
         else if (op == "stt") {
-            /*iss >> idstr >> deviceKey;
-#if OPENDHT_PUSH_NOTIFICATIONS
-            if (not deviceKey.empty())
-                dht->setPushNotificationToken(deviceKey);
-#endif // OPENDHT_PUSH_NOTIFICATIONS
-            dht->setProxyServer(idstr);*/
             dht->enableProxy(true);
             continue;
         } else if (op == "stp") {