Added an extra sort option for 'gilded'

Implemented 'gilded' sort both in the banner bar (by pushing the '6' key), and in the prompt (by entering '/subreddit/gilded')

rtv/submission_page.py

@@ -48,6 +48,10 @@ class SubmissionPage(Page):
     def sort_content_rising(self):
         self.refresh_content(order='rising')
 
+    @SubmissionController.register(Command('SORT_GILDED'))
+    def sort_content_rising(self):
+        self.refresh_content(order='gilded')
+
     @SubmissionController.register(Command('SORT_NEW'))
     def sort_content_new(self):
         self.refresh_content(order='new')