Add handlebars for JS templating

There is a convenient gem 'handlebars_assets' which will put any
handlebars template in assets/js/templates/(filename).hbs into a global
JS variable `HandlebarsTemplates['(filename)']`. This *should* work with
asset precompilation as well.

The main reason is maintainability... the candidate template had
spiraled out of control in complexity and this seems a lot more
reasonable to me.

The only downside is that you have to be a lot more explicit with the
variables / context you pass into the rendering, which is kind of a
drag because it requires more logic in the Backbone view. But that seems
relatively nice to me, since that means the view itself is much simpler.
Handlebars for the contributors list
Make search not reload the page

Backbone FTW!
Merge pull request #277 from tdooner/handlebars

Add handlebars for JS templating