Trigger a jquery event on error

In order to allow other modules to react to errors, this module can easily trigger an event, so those modules can bind handlers to that event.

For instance, here's a sample snippet for responding to an error:

  // Bind error handling.
  $('div.editablefields', context).bind('editablefieldsError', function (Event, element, response) {
    alert('Reacting to an editablefields error');
  });

Patch forthcoming.