Merge branch 'hotfix/3307' into develop

Forward port zendframework/zendframework#3307

Conflicts:
	library/Zend/Code/Generator/DocBlock/Tag/LicenseTag.php
	library/Zend/Code/Generator/DocBlock/Tag/ParamTag.php
	library/Zend/Code/Generator/DocBlock/Tag/ReturnTag.php

src/Helper/Placeholder/Registry.php

@@ -45,7 +45,7 @@ class Registry
     public static function getRegistry()
     {
         if (null === static::$instance) {
-            static::$instance = new self();
+            static::$instance = new static();
         }
 
         return static::$instance;