Embiggen control-bar click areas

Buttons in the control bar now take up the full height of the bar. Also, the click area of the far right button expands all the way to the corner. Fitts's law bla, bla, bla.

OLD:
![screen shot 2014-10-16 at 10 41 19 am](https://cloud.githubusercontent.com/assets/3692/4664251/8f4807ee-5542-11e4-9ad3-5c130b6998ad.png)

NEW:
![screen shot 2014-10-16 at 10 40 30 am](https://cloud.githubusercontent.com/assets/3692/4664253/9361ee12-5542-11e4-9b6e-b0253b12862a.png)