Allow 'options' to be given as array when adding a param detector - similar to env / options.

Allow the following when adding request detectors using CakeRequest::addDetector():

    array('param'=>'{param-name}', 'options'=>array())
Added test case for param with options detector.

Fix coding standards errors.
Merge pull request 1567 from calin-s into 2.5

Add ability to provide a list of valid param values when adding param
based detectors.

Refs #GH-1567