Issue988: preferences page needs a bit of love on narrow displays. Fix C...

This is a fix for the issue mentioned here:

https://github.com/hawtio/hawtio/issues/988

It used to look like this:

![screenshot from 2014-01-26 15 14 15](https://f.cloud.github.com/assets/1269759/2005092/08859a64-86d0-11e3-8a78-2f3c39d9da4a.png)


Solution 
Added a little javaScript magic and I think I fixed the issue. Here is a screen shot of it on openshift:

![screenshot from 2014-01-26 15 15 25](https://f.cloud.github.com/assets/1269759/2005089/c85cda38-86cf-11e3-97e2-5bc27c8a81f8.png)

On localhost hawtio it looks like this:

![screenshot from 2014-01-26 15 26 37](https://f.cloud.github.com/assets/1269759/2005090/ec32d4b2-86cf-11e3-8047-76db70194fc0.png)