Reveal - opening and creating within JS

Should fix eg. https://github.com/zurb/foundation/issues/3758

Closing by clicking on bg, X button or pressing ESC key now works properly when reveal is created and opened by javascript.

Example:

    var $div = $("<div class='reveal-modal' data-reveal><p>asd</p><a class='close-reveal-modal'>&#215;</a></div>");
    $div.foundation('reveal');
    $div.foundation('reveal', 'open');