[add] webapp on --host and --port (optionals)

src/dwatcher.ts

@@ -23,7 +23,7 @@ process.on('unhandledRejection', (err) => {
 
   try {
     const watchers: Watcher[] = await dwatch(argv.conf || path.join(__dirname, '../app.yml'))
-    webappServe(watchers)
+    webappServe(watchers, argv.host, argv.port)
   } catch (e) {
     console.error(e)
   }