adding parse_string method
adding null values generating an empty cell in table lib
diff --git a/system/libraries/Table.php b/system/libraries/Table.php
index a990d40..6d36121 100644
--- a/system/libraries/Table.php
+++ b/system/libraries/Table.php
@@ -260,7 +260,7 @@
 				{
 					$out .= $this->template['cell_'.$name.'start'];
 					
-					if ($cell === "")
+					if ($cell === "" OR $cell === NULL)
 					{
 						$out .= $this->empty_cells;
 					}