Show named substates

[rwjblue]

Added in 1.11: http://emberjs.com/blog/2015/03/27/ember-1-11-0-released.html#toc_named-substates

For example, given:

this.route('posts');
this.route('post', {path: '/posts/:post_id'}, function () {
  this.route('new');
  this.route('edit');
  this.route('comments', function() {
    this.route('new');
  });
});
this.route('signup');

A few of the named substates (in addition to the normal loading/error substates) would be:

application-loading
application-error
posts-loading
posts-error
post-loading
post-error
new-loading
new-error