fix the table cell colour issue in the new release for phoebus

Hi @yannmandza ,please check the update for the systemexpert, I have fixed the issue about the cell color fill in the table widget for the new release of phoebus. also I do some modification about the PVs read value by adding the XX.VAL but it seems like working sometimes not always, I think it might be some problem in the pvAcess.Please check and merge it.