Use spaces and capitalized words instead of underscored words.

![old](https://cloud.githubusercontent.com/assets/148768/2825795/219451da-cf5a-11e3-8f97-8d93b4dc46e0.jpg)
![new](https://cloud.githubusercontent.com/assets/148768/2825797/25f6f944-cf5a-11e3-837e-9859bfb20fbb.jpg)