Changing sort arrow fonts for consistency

Call me extremely nitpicky, but it was bothering me that the double sort arrow and the single sort arrow weren't the same width. Granted, I'm not at all sure how robust this "fix" is.

Before:

![screen shot 2014-11-03 at 9 18 19 am](https://cloud.githubusercontent.com/assets/322932/4883703/8aa5951e-6364-11e4-9165-8f5fcc71c7f6.png)

After:

![screen shot 2014-11-03 at 9 17 56 am](https://cloud.githubusercontent.com/assets/322932/4883704/8eca5b3e-6364-11e4-9116-0746e3a28c1e.png)