EmberAddon v2. config/environment.js support

@bantic to look at.

There is noise here from the addon assets being moved into `dist/`. This gives us the ability to configure Torii via the `config/environment.js` file in ember-cli addons.

/cc @rwjblue
I would suggest using `broccoli-string-replace` (see [details](https://github.com/stefanpenner/ember-cli/pull/1345)).

Also, requiring on initialization will slightly delay every command line invocation of `ember`.  I would suggest doing this inside the `treeFor`:

```javascript
treeFor: function treeFor(name) {
  this.replace = this.replace || require('broccoli-string-replace');

  /* rest of the current code here */
}
```