Changes

Removes jQuery dependency! This isn't quite as crazy as it seems, since most of our interaction happens within React elements. It cuts minified & gzipped script size from 112kb to 80kb.
Fixes an error that was introduced on the candidate page when changing thumbnail from a method to an attribute accessor in #334.
Cut the mustard and only run fancy client-side code on modern browsers. Old browsers (like Internet Explorer 8) will fall back to the server-rendered experience.

For review: @DoSomething/front-end

DoSomething / voting-app