Task stabilization improvement

> Using that task stach changes for maintaining the task order instead of
  using the UI load signals.
> On fast task switches, temporary task changes do not contribute to the task
  order. Only the final task is braught to the top of the list
> Removing and add tasks do not reset the order

Change-Id: I576cb4ffeec66e115acd327d58c59920c149aaca