Add button type to non submit button, add meta-helper class to meta editor buttons, cope with helper buttons in confirm-close.js, addresses #2226

The

chainHandler(window,'onload',function() {

confirmClosePage.getCurrentForms();

});

seems to be run before all DOM ready (with all js done), CKEditor or LegacyEditor? add some stuff to current form after that ?!?
a 1 second delay to run again confirmClosePage.getCurrentForms() is not enough…