Miscellaneous general classes, especially the util classes to handle a user notifications, displaying dialogs and wizards.

See `DialogDisplayer` and referenced classes for displaying dialogs.
See `NotifyDescriptor` which provides a description of a user notification to be displayed.
`WizardDescriptor` is the framework provides creating and handling dialogs which leads a user step-to-step through task. See also `wizard guidebook` which describes the set of properties controls the wizard panel's layout.