Accessibility improvements

I added a directive that will keep the element it is attached to up to date with the check status - updating the icon and color to display contextually relevant information.

In this PR I have also updated some outdated dependencies to work around an old karma/phantomjs issue - unrelated but should be safe.

Finally, I changed the Stashes icon from `fa-database` to `fa-briefcase` - I would like to gather consensus but the aliasing on the database icon at that size detract from the look of the page in my opinion.

This PR would partially resolve #80 
How about:
```javascript
var styleMap = { 'critical': 'danger', 'unknown': 'muted'};
style = styleMap[style] ? styleMap[style] : style;
```