Cleaner, mostly-functional version of dynamic panes!

Using views where I had been using crazy helpers to no effect.  Got rid
of the weird array of strings and using real Ember templates.  Most
importantly, updates to the data are actually updating the view.  The
missing piece is it won't render panes that haven't had anything
assigned to them, nor is there anything in the markup to show which slot
in the pane that the templates are being rendered inside of.
Properly show panes that haven't been assigned.

In the quarters layout, maybe you haven't assigned the top-right pane
yet.  You want the other three to have their markup showing the proper
position, and you should render placeholder markup for the unassigned
pane.
Cleaned up board markup and added styling hooks.

And hideously ugly styles that are technically accurate.
Upgrade ember-rails, lock it up.

There's some problems with handlebars rc2 (maybe) and the slightly older
version of ember-rails (definitely).

https://github.com/emberjs/ember.js/issues/1827
Replace deprecated #controllerFor with #needs.
Update ember and use up-to-date route hooks.