Make the historical views more sensible

[antialiasis]

It would make the most sense for all the historical views (as I count it, that means the all nominations, user nominations, admin nomination, and eventual results views) to have a year kwarg at the front (so /2014/nomination/all/ rather than /nomination/all/2014/), with just /2014/ leading to a kind of historical home view. (Perhaps that should just be the results view?) When the year kwarg is set, the year context variable for the templates is set as well - everything should say 2014 if we're viewing stuff from 2014. Make sure this doesn't break anything (unlikely, but just in case). Could use a mixin class that can just be dropped in to make it work.

Then we'll obviously want some sort of page linking to previous award views.