Ember TED Collapsible Panel

[romulomachado]

Same thing as #13.

Since we're not doing anything too specific with ember-ted-collapsible-panel, I'm keen to go with a community used solution like rc-collapse.

@jonbellah What do you think?

[jonbellah]

@romulomachado Seems like a good enough solution. I don't think this would be too difficult to implement ourselves, but a styled wrapper around this would be fine, as well.