Fix compatibility with Calibre 0.9.16 (revision 14170): get_browser() is now an instance method.

As of Calibre 0.9.16, BasicNewsRecipe.get_browser() is now an instance method, and self must be passed as the first argument. For background, see:

http://www.mobileread.com/forums/showthread.php?t=204109 http://bazaar.launchpad.net/~kovid/calibre/trunk/revision/14170