add readback value widget for all the TB elements in the Main screen

git-svn-id: svn+ssh://controls01/siciliarep/svn/trunk/tango_client/ctlinac/trunk@13046 a18efa20-c439-0410-bf20-9b91ec695b4c
Change the Linac's MainWindow class to inherit from TaurusGui to add the panels feature as a first approach to add plots as user request.

git-svn-id: svn+ssh://controls01/siciliarep/svn/trunk/tango_client/ctlinac/trunk@13047 a18efa20-c439-0410-bf20-9b91ec695b4c
fix mistake building the vacuum leds, they where using directly setModel() instead of the builder _setupTaurusLed4Attr()

git-svn-id: svn+ssh://controls01/siciliarep/svn/trunk/tango_client/ctlinac/trunk@13048 a18efa20-c439-0410-bf20-9b91ec695b4c
modifications in the background drawing, then many widgets has been moved a little bit.