emptyValue enhancement and default settings handling via Configure()

*  default settings handling via Configure()
*  `emptyValue` default values to allow search for "not any of the below"
* code fixes and corrections
* more tests

Configure::read('Search') is quite useful, as you can set (DRY) app wide global settings, while still applying quite different ones throughout the dozens of controllers:

    $config['Search'] = array(
	'Prg' => array(
		'commonProcess'=>array('paramType' => 'querystring', 'filterEmpty' => true),
		'presetForm' =>array('paramType' => 'querystring')
	),
	'Searchable' => array(),
    );

Let me know what you think about it. I could also split them. Just squashed and rebased as it was quickest.