Slightly changed hint text

Hint text under fields in Configuration should be more obvious and readable.

I didn't changed much, but it makes big difference for some users.

My reason for the changes is to improve the visibility of the hint text for users who use MODx / Bootstrap template and for clients who just want to click here or click there.

![hint-text-after](https://cloud.githubusercontent.com/assets/9590122/4953541/1de378da-6682-11e4-9d44-369749ad469e.jpg)
![hint-text-before](https://cloud.githubusercontent.com/assets/9590122/4953540/1de36e8a-6682-11e4-898f-d693987c0b48.jpg)