Expose 'link' as 'compose'; this facilitates implementation of
drag-drop composition being deferred to actions which will
support move/copy/link options in the future. WTD-962.
Invoke persist calls when leaving Edit mode in a group, instead of
in-order, to allow these revision-checking to be handling for the
group as a whole. WTD-1033.
Add directive for exposing expressions which should be
evaluated for the browser's onbeforeunload event, to
prevent user-initiated navigation from causing a loss
of unsaved changes. WTD-1035.
Update the root object (used to populate the Library pane)
less often, to avoid recreating the whole tree and thereby
causing the tree to collapse. WTD-788.
Add a commit function to scope from the edit representer;
this avoids issues trying to transparently detect and
persist changes made during edit mode, while still requiring
only minimal action from individual views. WTD-535.
Add an EditRepresenter which detects changes to domain
object model or view configuration and, when these
occur, triggers mutation and persistence of the domain
object. (Note that in Edit mode, 'persistence' only
flags an object as dirty; actual persistence does not
occur until the user chooses Save.)
This supports editing of position/size in Layout mode,
and the persistence of those changes. WTD-535
