Add histogram to compare page

Updates on compare delete
Replaces calloutValues and calloutColors properties
of the histogram-directive with two way bindings, fixed broken
detail histograms

![mos-compare](https://cloud.githubusercontent.com/assets/1818302/5403654/602c7bb6-815c-11e4-9f0c-935955cd43b9.png)

There's a special sector color with the key 'Unknown', for null/unmatched sectors.  Instead of keying off `MOSColors` directly, it would be good to check if it has the key first, then grab the 'Unknown' value if it doesn't.