grid row missing default formatting

[jeff-preload]

Needs padding and border bottom like other fields to standardize formatting.

Can be achieved by adding default cmb2 class 'cmb-row' to line 29 of cmb1-grid/Grid/Row.php when row is generated.

ie.
$field->args['before_row'] .= '<div class="row cmb2GridRow">';
->
$field->args['before_row'] .= '<div class="cmb-row row cmb2GridRow">';