Side by side diff view. fix: #126

Side by side diff view is now available within detailed diff view.

* using [diff2html node](https://www.npmjs.org/package/diff2html) which is based off of [diff2html](https://github.com/rtfpessoa/diff2html).  It's an MIT licensed project.
* raw git log of a file is transferred to client side and diff2html on the client side does the parsing and uses diff2html view.  We can move the parsing to the server side and build our own view but i'm super lazy and diff2html's side by side view isn't half bad at all.
* the way multiple text diff type is managed is little sloppy within various components.  I want to push this big change in and then clean it up by creating a component that manages multiple text diff components. 


![screen shot 2014-11-30 at 1 16 28 pm](https://cloud.githubusercontent.com/assets/5281068/5239350/68a5984e-7893-11e4-80ce-6f29759390f4.png)
![screen shot 2014-11-30 at 1 16 20 pm](https://cloud.githubusercontent.com/assets/5281068/5239351/68bfc6b0-7893-11e4-8630-94f8d66982c4.png)
This component seems to be doing very little and it doesn't have any template associated with it. Maybe it's better to just have similar code in the two places it's used instead?