New: Number formating helper

- I've come accross a lot of cases recently where numbers need to be
  formatted for display, so I wanted to introduce rendering helpers for
  DataTables to make this easier. Only one helper introduced here -
  `$.fn.dataTable.render.number()` which will return an object that can
  be used by `columns.render` to format "raw" numbers.
Update: The `_` option for columns.render as an object is optional now

- Previously when using columns.render as an object, you had to supply
  an `_` option which was the fallback. However, I've now made it so
  that if there is no `_` option it will just use the raw data from
  `columns.data`
Fix: Fix display issues with HTML5 attributes example
Fix: Example JS should use min-height for info content
Dev fix: Sort classes for cells were broken in beta.3-dev

- Commit 515761905c had removed the `_fnSortingClasses` call for a
  client-side processing table without defered rendering.
Fix: Ordering informationw as being sent in SSP Ajax when ordering disabled

- See thread 19860 for details.