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: Ib2054285efb07ccbfaf3faf089085c16ba432be8
Reviewed-on: http://codereview.qt.nokia.com/22


Reviewed-by: Daniel Teske <daniel.teske@nokia.com>