Changed the method by which JS events could be added before and after form submission. Previously, a proprietary function registration system was used. In this version, however, this system has been dropped in favor of the jQuery event method. Ninja Forms will now fire a custom event of "beforeSubmit" before a form is submitted. Returning false in a function handler on this event will cause submission to be cancelled. "submitResponse" is the custom event fired by Ninja Forms when a form has been submitted. See includes/js/dev/ninja-forms-display.js for details in the comments.