Fix context help for examples

- createRightPaneContextViewer() needs to be called up-front. In the old
order, it would fail the first time.

- Queue opening of help, because we need the editor window to be drawn
  before it can be assessed wether to show the help in split mode

Change-Id: Ib2054285efb07ccbfaf3faf089085c16ba432be8z
(cherry picked from commit c86e81c3)
Reviewed-on: http://codereview.qt.nokia.com/149


Reviewed-by: hjk <qthjk@ovi.com>