Fix: State saving + server-side processing wasn't working

There were a number of issues here:

* When virtual scrolling, the 'floatTop' parameter wasn't available for
  the table position calculation, which results in the table being
  incorrectly positioned. The extra variable needs to be stored in state
  as well.
* When server-side processing, DataTables' draw callback for the first
  draw is the one we want to operate on, unlike Ajax sourced client-side
  data where it is the second draw (this should probably be corrected in
  DataTables).
* To stop layout trashing we need to ignore the scrolling events during
  initialisation when state saving is enabled.
Merge branch 'master' of github.com:DataTables/Scroller

Conflicts:
	js/dataTables.scroller.js
Dev: Update server-side example to be more like server-side processing
with a small delay