ZF-4617: Improve docblock
According to discussion of SL-13 setDescription needs additionally docblock informations:
Solution: ADD A SHORT DESCRIPTION IN THE DOCBLOCK !!!
Information: Quality is what users can set in their browser... it is defined by HTTP and has a value from 0% to 100%. This is where the value of 0-1 comes from as it is exactly set the same way in browsers which support this. These are float values as per definition from HTTP 1.1.