Switch CI_Form_validation:: to public

Makes it easier to access the data after validation (issue #1208)
diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index d3d22c5..04bb81d 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -105,7 +105,7 @@
 	 *
 	 * @var array
 	 */
-	protected $validation_data	= array();
+	public $validation_data	= array();
 
 	/**
 	 * Initialize Form_Validation class