Show active sessions in bold.

Before 
![session-active1](https://cloud.githubusercontent.com/assets/991300/4664454/11bceca2-5544-11e4-8aab-35bb8b549e96.png)

After
![session-active](https://cloud.githubusercontent.com/assets/991300/4664456/177080f0-5544-11e4-9566-27059eee5936.png)

 Fixes #84