Please add hooks/events/callbacks

Hi,

nice plugin (I purchased premium), but please add some hooks to it.

I’d need to manipulate the input before it is saved. A simple `$booking_data
= apply_filters( ‘wpbs_submit_form_booking_data_before_save’, $booking_data );` in /includes/base/form/funcitons_ajax.php would be sufficient.

Also, a JS event after successful submit would be really nice, like i.e. CF7 does it.

Thank you.