Implement identifier name property

- Added $identifierName property
- Added mutator and accessor for $identifierName
- Modified getIdentifier() to use the $identifierName when attempting to
  retrieve the resource ID.

library/Zend/Mvc/Controller/AbstractRestfulController.php

@@ -38,6 +38,13 @@ abstract class AbstractRestfulController extends AbstractController
         )
     );
 
+    /**
+     * Name of request or query parameter containing identifier
+     * 
+     * @var string
+     */
+    protected $identifierName = 'id';
+
     /**
      * @var int From Zend\Json\Json
      */
@@ -50,6 +57,28 @@ abstract class AbstractRestfulController extends AbstractController
      */
     protected $customHttpMethodsMap = array();
 
+    /**
+     * Set the route match/query parameter name containing the identifier
+     * 
+     * @param  string $name 
+     * @return self
+     */
+    public function setIdentifierName($name)
+    {
+        $this->identifierName = (string) $name;
+        return $this;
+    }
+
+    /**
+     * Retrieve the route match/query parameter name containing the identifier
+     * 
+     * @return string
+     */
+    public function getIdentifierName()
+    {
+        return $this->identifierName;
+    }
+
     /**
      * Create a new resource
      *
@@ -439,12 +468,13 @@ public function addHttpMethodHandler($method, /* Callable */ $handler)
      */
     protected function getIdentifier($routeMatch, $request)
     {
-        $id = $routeMatch->getParam('id', false);
+        $identifier = $this->getIdentifierName();
+        $id = $routeMatch->getParam($identifier, false);
         if ($id) {
             return $id;
         }
 
-        $id = $request->getQuery()->get('id', false);
+        $id = $request->getQuery()->get($identifier, false);
         if ($id) {
             return $id;
         }