Plugins with classes that extend Managed_DataObject get better code reuse

The switch to having a function in Managed_DataObject is now being applied
to plugins which can use this as well.

There are some plugins that still use Memcached_DataObject, but these will
be taken care of later.

plugins/QnA/classes/QnA_Question.php

@@ -55,22 +55,6 @@ class QnA_Question extends Managed_DataObject
     public $closed;      // int (boolean) whether a question is closed
     public $created;     // datetime
 
-    /**
-     * Get an instance by key
-     *
-     * This is a utility method to get a single instance with a given key value.
-     *
-     * @param string $k Key to use to lookup
-     * @param mixed  $v Value to lookup
-     *
-     * @return QnA_Question object found, or null for no hits
-     *
-     */
-    function staticGet($k, $v=null)
-    {
-        return Memcached_DataObject::staticGet('QnA_Question', $k, $v);
-    }
-
     /**
      * Get an instance by compound key
      *