Switch to history-based routing.

This makes it easier to bookmark URLs and come back to them at a later
time, which goes along very well with the search-as-resource paradigm
introduced in previous commits.

Browser compatibility isn't as good as the anchor-based method, but
we're really only supporting recent-ish versions of Firefox for now, and
I know that this works in Chrome and Safari too.  (What that really
means: lower versions of IE are out.)
"Study locations" will be more familiar verbiage.
More resource rearrangement.

I read Ember.js' router code over the weekend, and it occurred to me
that the routing guides on emberjs.com didn't really tell the whole
story.  In particular I did not previously know that this was possible:

  @resource 'event_searches', ->
    @resource 'show', path: '/:event_search_id'

Now, all of that is *inferrable* from the guides, but not spelled out.
(What can I say, I'm not very good at inference.)

Anyway, after reading said code, I was inspired to clean up the event
search routes.

This moves things much more in line towards one-controller-per-outlet
(not a requirement, but often a useful pattern).