Added sorting to array controller guide and a deeply nested route example

I felt this documentation addition to be helpful. This is in response to https://github.com/emberjs/ember.js/pull/3069 as well.

![arraycontrollersorting](https://f.cloud.github.com/assets/12481/910610/5c251bbc-fddd-11e2-8cf9-c07e39d41934.png)

![deeply-nested](https://f.cloud.github.com/assets/12481/910611/5dbc4928-fddd-11e2-8f2d-f988e9806d0c.png)