Reference static property, well, statically.

Currently, with strict reporting enabled, a notice is being thrown for a rather simple oversight, that you've got a static property, `$included`, but you are referencing it as an object instance property.

![screen shot 2013-09-19 at 9 58 40 am](https://f.cloud.github.com/assets/181919/1169839/79ae3ac0-20be-11e3-9d92-197d11b563ce.png)