..ui.util: adding property chnage support for MultiSelectionCombo widget

Change-Id: Ia4b656c2904ae3076dfc2bcd7929176b7412b84b
..LogEntryWidget: adding selection change listener for the
multiselecitoncombo

Change-Id: I3a9cb797abf7743f2e61c2251e258f034558e71d
Merge branch '3.2.x' of ssh://git@github.com/ControlSystemStudio/cs-studio.git into 3.2.x