workspaces view can now be any view in the hierarchy.
* Added private view flag kWorkspacesViewFlag that identifies such a
view - note though, that you must not remove a view before closing or
hiding its window for now (and that you still need to set the
kWorkspacesWindowFlag, too).
* Fixed Workspaces check for valid screen coordinates; after a crash, it
managed to open its window offscreen for me.
* Added a ViewLayer method FindView() that finds a view with the
specified flags set.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24090 a95241bf-73f2-0310-859d-f6bbb57e9c96
