Changes: Mark placeholder quicklaunch buttons so that they are correctly identified and deleted
Changes: Mark placeholder quicklaunch buttons so that they are correctly identified and deleted

RevBy: Ran Nyman
Details:
 - Mark placeholder widgets with a "placeholder" property so that they
   are deleted correctly on data update.
 - Set placeholders' object name to QuickLaunchBarButton so that they
   can be identified in functional tests.

pvuorela/lipstick,sletta/lipstick,sletta/lipstick,giucam/lipstick,matthewvogt/lipstick,rainisto/lipstick,rainemak/lipstick,adenexter/lipstick,sletta/lipstick,rainisto/lipstick,rainemak/lipstick,pvuorela/lipstick,giucam/lipstick,rainisto/lipstick,matthewvogt/lipstick,jusa/lipstick,adenexter/lipstick,giucam/lipstick,matthewvogt/lipstick,pvuorela/lipstick,rainemak/lipstick,jusa/lipstick