Update the layout support to take a "-" to indicate that a view should be removed (or hidden) in addition to the + used to indicate multiple views will be displayed.  Tests have also been updated to test this support.  The way defaultTransition was working has also been updated to allow a transition set on a transition event to take precedence over the defaultTransition set in the config. But there are cases where an app would like to override the transitions via the config, so I have added another config option "transition" which will take precedence over the transition set on the event.