New: Ordering functions for the new API:

- order() and order.listener() added (to replace fnSort and
  fnSortListener) from the old API.

- Note that the name `order` is selected to not conflict with the `sort`
  method of the API object, which can be used to order the sort data
  held in the collection.

- The `sort()` method is expanded over the abilities of fnSort to allow
  multiple different forms of input (column + direction, 1D array, list
  of 1D arrays or a 2D array).
Internal - Small change to the new order() method to remove redundant code