Fix hot reload resetting whole renderer state

From SimulatedGREG#437

Author: Egor3f

template/.electron-vue/dev-runner.js

@@ -64,8 +64,9 @@ function startRenderer () {
       {
         contentBase: path.join(__dirname, '../'),
         quiet: true,
+        hot: true,
         before (app, ctx) {
-          app.use(hotMiddleware)
+          // app.use(hotMiddleware)
           ctx.middleware.waitUntilValid(() => {
             resolve()
           })