Support rendering with additional context in Config.ListItemView
Review Request #9075 - Created July 13, 2017 and submitted
Djblets.Config.ListItemViewnow supports an additional method,
getRenderContextthat will be used with the associated model's
attributes to generate the full render context for the template. This
allows subclasses to inject things into the template that are not
necessarily model attributes (but my be derived from them).
Tested this with an upcoming patch for Review Board.