Fix: Ajax data wasn't being sent for non-server-side processing

- If you used client-side processing ajax, the parameter passed into
  _fnBuildAjax is an array, needed for the old 1.9 compatiblity, but the
  ajax wasn't transforming this into a data object and then sending it
  to the server. The fix is to check if the data passed in is an array
  or not - if so, transform it to an object