Adds a feature to check argument names

Flag the arguments colliding with `clojure.core` public functions

Output looks like:
![screen shot 2014-11-22 at 21 12 59](https://cloud.githubusercontent.com/assets/407891/5155491/c24db546-728c-11e4-99f5-b8a9487d8ad1.png)

Can you change this to spaces instead of a tab?