fix for 'Object doesn't support this property or method' on IE8

fix for 'Object doesn't support this property or method' on IE8, when this browser tried to iterate through array (this.lists) using 'indexOf' key (instead of it's own properties)

![image 2014-07-18 at 12 49 55 pm](https://cloud.githubusercontent.com/assets/1146430/3625742/bdae2b08-0e71-11e4-9dea-6eee615af1ae.png)