* Deprecate set but unused Status property in favour of ProgressDescription.
* Deprecate set but unused TitlePlan property.
* Deprecated property Title in favour of ProgressDescription.
* Removed unused plan RebootHostPlanAction.
* Updated event declaration.
* Removed property Visible. The plan is to have the actions log their history as soon as some is available.
* Reworked the logging for the plan actions. The main change is the replacement of
the ProgressDescription with a stack where all the steps of an action are stored,
i.e. the action is responsible for its history, not the worker running it.
* Lock the progress history before accessing it.
* Better handling of error logging and user cancellation.
Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
