title: Prevent mqtt.js to disconnect in browser
body: <h2>Short</h2>
  <p>Is there a way of preventing mqtt in the browser to disconnect when the browser loses focus?</p>
  <h2>The long one</h2>
  <p>Previously I used Paho mqtt from a browser talking to a secure web socket.
  Paho sometimes had trouble setting up the connection with Paho therefore we changed to mqtt.js</p>
  <p>I find it much better at setting up the connection.</p>
  <p>But, when I leave the browser for a while it seems to disconnect, however it connects really quick again when the tab gets the focus back.</p>
  <p>I can see the reason for having a timeout function, but it should be possible to turn it off.</p>
  <p>Is it?</p>