First pass at fixing #273.

 It would be nice to add the reply field at the bottom of the notifications screen,  without opening the web-browser, or the near to be implemented in the native reader, the AuthenticatedWebView (#175).
This is probably something we can do later, when comments unification is completely done. Also, this feature is only available for a small group of lucky people, I don't think we no need to spent more time on this at the moment.