Adding --with-24-bit to tmux formula

Add's 24bit color sequences option to tmux. It's currently just applying a patch if the option is provided.

![screen shot 2014-11-09 at 10 16 59 am](https://cloud.githubusercontent.com/assets/360409/4967767/7c7fa74a-6823-11e4-8d69-c99d94d6df91.png)