Keep track of state/content between multiple quotes in a single post

Fixes #142 (which I could still reproduce; I'm happy to spell it out more if others aren't seeing it).

This is my Ember-naïve approach, leaning on jQuery `$aside.data()`. A more Embery approach might be to introduce a Quote JS model that keeps track of its own expanded state and full quote content, and then Posts could have many Quotes? I'd love to see a more Embery way of solving this problem.

I don't know how to test this either, it seems there aren't already established tests for JS views or user-story-style integration tests...