PtPanelGroup and PtWebClient

PtPanelGroup build the tab’s name from the Pt_ARG_TITLE of it’s child.

The problem is that the PtWebClient, which is a descendant of
Pt_Container, doesn’t have a Pt_ARG_TITLE available from phAB’s resource
editor so, we need to add a Pt_Pane to define the tabs titles.

Could the photon team add the Pt_ARG_TITLE ressource access?