improve dehub navigation bar (bug 750904)

(moved from [zamboni/pull/1752](https://github.com/mozilla/zamboni/pull/1752))

https://bugzilla.mozilla.org/show_bug.cgi?id=750904

What that does:

- change the red title (h2) to display add-on name
- modify navigation panel to only bold current link
- create the new "status box" at the top
    - add version information (current/latest version, position in the review queue)
    - add tooltip on status
    - add specific information when a version is being reviewed/rejected

![devhub status box and nav panel](https://f.cloud.github.com/assets/167767/2139483/547d9108-933f-11e3-962b-0aff46308252.png)