QUICKFIX - dont sort on every add in pageable col

  Sort gets called after event add, which meant the collection was
  always being reset and the list view re-rendered. This was especially
  slow when used in conjuction with a filtered collection. Removing a
  filter could trigger 100s of add events. I now have to trigger a sort
  after each add to tell the list view to re-order the elements on the
  page. Also needed to upgrade to latest backbone to know if the sort
  event was coming from an add.