Code review comment for lp:~rharding/juju-gui/update-urls

*** Submitted:

Rearchitect the browser to use routes more

- Use nested routes and route handling to build the browser UI
- Break up the Views in the browser subapp to be more singular per UX
component.
- Adjust tests to fit with this.

R=jeff.pihach, j.c.sackett
CC=
https://codereview.appspot.com/8679045

https://codereview.appspot.com/8679045/