* Moves handling which models are in the selection into the `Library` state. * Adds highlight for the last-selected view in a multi-view state. * A view must be the last-selected view before it can be deselected. see #21390. git-svn-id: http://core.svn.wordpress.org/trunk@22332 1a063a9b-81f0-0310-95a4-ce76da25c4cd