Fixed json content type

I've done a test on Backbone without jQuery, and when I've used Backbone.NativeAjax I've founded this situation. 

On my BackboneView I've coded a collection.fetch(); and when I've seen the json return on console (console.log(this.collection)), this happened.
![screenshot 2014-07-03 19 53 48](https://cloud.githubusercontent.com/assets/2637502/3476735/514e4720-0306-11e4-9116-b020e3e6c0c3.png)

So, I've modified the line 24 on your code, changing 
This line
    var jsonRe = /^application\/json/;
For this
    var jsonRe = /^text\/json/;

I've just modified the content-type, then the return on console
![screenshot 2014-07-03 19 54 18](https://cloud.githubusercontent.com/assets/2637502/3476773/ee24d2da-0306-11e4-878a-20532c954b8e.png)

So it is ;-)
`Var` here isn't in my repo... Don't know where this came from