Fix: Right column blocker above the vertical scrollbar was being shown
based on horizontal scrolling rather than vertical as it should be
New: Alter column sizes dynamically when DataTables does

- This is done by listening for the new `column-sizing` event from
  DataTables 1.10. When fired, we read the new sizes of the columns from
  DataTables and apply to our layout.

- This allows FixedColumns to be used in a dynamically resizing table.