Plasma/Activities

activities, whee...

functionality

• when plasma is locked, the activitymanager runs away. it shouldn't do that; instead it should disable the add/remove buttons (and maybe stop/play too?)
• we need a way to rename and set icon from the activity manager. that's the stuff that was in the containment config for 4.5
• support switching to other-screen containments (explained better on the Multiscreen page