Fix vendored file versions.

Pull request #54 changed the bower config to use Ember 1.0.0-rc.6
(because the [components/ember](https://github.com/components/ember)
repo isn't updated for 1.0.0-rc.6.1 yet), but it did not update the
vendored version of ember.

Pull request #37 changed `public/index.html` to use `handlebars.js`
instead of using the runtime component (`handlebars.runtime.js`) because
the runtime component wasn't explicitly added to the repo as part of #26.
This PR adds `handlebars.runtime.js` back into this repo, and reverts
the changes from #37 (meaning that we now use the runtime only). This
should resolve #40.

The required version of `grunt-ember-templates` was changed to `0.4.10` in
0d00bacf86c92e7a24b036ea788c2ad03d41e363, but since `ember-1.0.0-rc.6`
can't use `handlebars-1.0.0` we must hard code our dependency to
`grunt-ember-templates-0.4.9` (which uses `handlebars-1.0.0-rc.4`).

To recap:

* Reset our vendored files to `ember-1.0.0-rc6`, `handlebars-1.0.0-rc.4`,
`grunt-ember-templates-0.4.9`.
* Update `public/index.html` and `tests/index.html` to use
`handlebars.runtime.js`.
* Should resolve #40.