various UI fixes

In preparation to the upcoming cider-theme ;)
Depends on <https://github.com/cider-ci/cider-ci_user-interface/pull/4>
Squash as needed.

## Visual Changes:

1. If a **semver pre-release version** is running, show the version (without the build data) in the navbar next to brand
    ![screen shot 2014-12-14 at 15 17 33](https://cloud.githubusercontent.com/assets/134942/5427598/e6a1fe46-83a5-11e4-8a3a-320e396006c1.png)

2. Executions-Table colors are toned down, but a border is added
    
![screen shot 2014-12-14 at 15 13 50](https://cloud.githubusercontent.com/assets/134942/5427599/f622a6a4-83a5-11e4-928b-1eee8f8a7751.png)