Allow 'options' to be given as array when adding a param detector - s…

…imilar to env / options.

Allow the following when adding request detectors using CakeRequest::addDetector():

    array('param'=>'{param-name}', 'options'=>array())

lib/Cake/Network/CakeRequest.php

@@ -516,8 +516,13 @@ public function is($type) {
 		}
 		if (isset($detect['param'])) {
 			$key = $detect['param'];
-			$value = $detect['value'];
-			return isset($this->params[$key]) ? $this->params[$key] == $value : false;
+			if (isset($detect['value'])) {
+				$value = $detect['value'];
+				return isset($this->params[$key]) ? $this->params[$key] == $value : false;
+			}
+			if (isset($detect['options'])) {
+				return isset($this->params[$key]) ? in_array($this->params[$key],$detect['options']) : false;
+			}
 		}
 		if (isset($detect['callback']) && is_callable($detect['callback'])) {
 			return call_user_func($detect['callback'], $this);