Upgrade to latest version of django-rest-framework

### What is the problem / feature ?

Project was running an old version of [django rest framework](http://www.django-rest-framework.org/)

### How did it get fixed / implemented ?

Upgraded to latest release (`2.4.0`)

### How can someone test / see it ?

Code

*Here is a cute animal picture for your troubles...*

![rehab-facility_volunteers_dog-deer](https://cloud.githubusercontent.com/assets/824194/4509504/fc90224a-4b20-11e4-87da-84efd63388a5.jpg)