Safari: get appinfo from tooltip
Firefox: new method for request handling

Now both nsIContentPolicy and on-http-* observers are used for net request
monitoring.

Reasons:
 - In many cases, nsIContentPolicy.shouldLoad is invoked twice for the same
   resource, because of the speculative parsing.
 - nsIContentPolicy.shouldLoad don't have information about the channel,
   so it can't redirect the request, nor change its headers, however
   on-http-opening-request can.

Also, local mirroring and inline-script blocking has been implemented.
Popup related changes