Moved the data table sort icons next to the column headings.

@rocha @clintonb 

FYI: @shnayder @marcotuts 

Before:
![before-ff](https://cloud.githubusercontent.com/assets/5265058/4391303/0866af7c-4404-11e4-9619-050fb4bc8d58.png)

After:
![after-ff](https://cloud.githubusercontent.com/assets/5265058/4391304/086f3a66-4404-11e4-9170-e4f1a50f0770.png)