function addRow(gui, newDom, liBefore) {
	  var li = document.createElement('li');
	  if (newDom) {
	    li.appendChild(newDom);
	  }

	  if (liBefore) {
	    gui.__ul.insertBefore(li, liBefore);
	  } else {
	    gui.__ul.appendChild(li);
	  }
	  gui.onResize();
	  return li;
	}
Add a row to the end of the GUI or before another row.

@param gui
@param [newDom] If specified, inserts the dom content in the new row
@param [liBefore] If specified, places the new row before another row