attempt two at implementing feeds

got as far as creating a separate route for feeds and trying to use
outlets to render it on the page... but couldn't render both models
simultaneously.
very vague progress towards rendering feeds
managed to get composite models working on routes

the key is that the todos/index route is the one that is displayed, and
is the only one that can actually render templates; I am guessing that
routes do not call parents except to mess things up. so by moving the
renderTemplates into the child todos/index route, we can render the two
outlets separately (but I guess it means we have to duplicate the
renderTemplates for each outlet on each route/view).
cleaning up code, implementing test feed data

clarifying the architecture and choices with lots of documentation and
comments.