Network viz fixes

On the network view, fix the source average line's location (x coordinate) and height (y length). Fixes part of #135, but not all of it. Includes #144 .

![screen shot 2014-06-17 at 3 40 02 pm](https://cloud.githubusercontent.com/assets/526415/3307989/c2a787b8-f674-11e3-830b-65e4137700be.png)