default:session support?

Would love if support of default:session would be added.

Just a few lines to add in function get_default_option (file: includes/form-tag.php)

			} elseif ( 'session' == $opt and isset( $_SESSION[$this->name] ) ) {
				$vals = (array) $_SESSION[$this->name];
				$vals = array_map( 'wpcf7_sanitize_query_var', $vals );

				if ( $args['multiple'] ) {
					$values = array_merge( $values, $vals );
				} else {
					$val = isset( $vals[0] ) ? (string) $vals[0] : '';

					if ( strlen( $val ) ) {
						return $val;
					}
				}

Thanks
Digo