ref #7086, #7095 Adapt working set navigator to work with WorkingSets
ref #7086, #7095 Adapt to cdm model changes
ref #7086, #7095 Add WS perspective
ref #7086, #7095 Add create/delete handler to WS navigator
ref #7086, #7095 Added "Open in..." menu for WS and matrix editor
ref #7086, #7095 Implement working set navigator