Change the color of result printouts in IEx

![Screen Shot 2013-02-27 at 7 35 55 AM](https://f.cloud.github.com/assets/452/201438/8d8ccb08-80f3-11e2-8104-8244201f8b04.png)
![Screen Shot 2013-02-27 at 7 35 25 AM](https://f.cloud.github.com/assets/452/201439/8d90e3f0-80f3-11e2-9841-ae2610e27735.png)
![Screen Shot 2013-02-27 at 7 35 04 AM](https://f.cloud.github.com/assets/452/201440/8d904e86-80f3-11e2-8537-fe267797e8aa.png)
![Screen Shot 2013-02-27 at 7 35 36 AM](https://f.cloud.github.com/assets/452/201441/8d934e6a-80f3-11e2-93ea-d55cb065311d.png)
![Screen Shot 2013-02-27 at 7 35 15 AM](https://f.cloud.github.com/assets/452/201442/8d8fca88-80f3-11e2-8ad3-806475b14ffe.png)
![Screen Shot 2013-02-27 at 7 34 46 AM](https://f.cloud.github.com/assets/452/201443/8e6e2df0-80f3-11e2-8af9-84a10a3bc6ae.png)