function getLayoutItem(layout
/*: Layout*/
, id
/*: string*/
)
/*: ?LayoutItem*/
{
  for (var i = 0, len = layout.length; i < len; i++) {
    if (layout[i].i === id) return layout[i];
  }
}
Get a layout item by ID. Used so we can override later on if necessary.

@param  {Array}  layout Layout array.
@param  {String} id     ID
@return {LayoutItem}    Item at ID.