A bug fix, a clarified Async task structure

Hello there,

Please let me thank you for your great library, it saved me a lot of time.
I've integrated it yesterday and I discovered a few issues with it.

I've made a quick patch for bug when the requets is made offline. The InputStream is then null and crashed the parser.

I have also separated the UI work from the ASync task in Routing.java

Please feel free to integrate or not these small changes.

Thanks a lot again for this lib!
Cheers,
Cyrille