requested by gareth.j

It would be great to have an easy way to add URL to Hudson build monitor
preferences.
At the moment (0.8), you have to copy the feed URL from the main window, then
open up preferences window and paste the URL.

It's much easier to have the user right click on a link, and the option "add to
BuildMonitor" should appear. When selected, the preferences page can show up
with the URL already copied, so the user only need to give it a name and save
the prefs.