Bugfix: (manual merge from a pull request from amironov) Work item GH-82 - PHPExcel_Worksheet::getCellCollection() may not return last cached cell

Classes/PHPExcel/CachedObjectStorageFactory.php

@@ -236,4 +236,12 @@ class PHPExcel_CachedObjectStorageFactory
         return FALSE;
     }   //    function getInstance()
 
+
+	public static function finalize()
+	{
+		self::$_cacheStorageMethod = NULL;
+		self::$_cacheStorageClass = NULL;
+		self::$_storageMethodParameters = array();
+	}
+
 }