Add propogating selection to attribute panel feature

This MR introduces a feature that if user does a selection in model tree or render view, it would update the attribute panel.Switching tabs, creating and copying new definition would also preserve selection.

qtSelectionManager is also exposed to qtUIManager. A logic error is fixed for qtSelectionManager so that when selected from attribute panel, we would only update selection once.

cc @bob.obara

Close #123 (closed)