Fixed Bug #4591: eventsInRange() called twice during startup on some canvases.
Bug #4082: Welcome note should be displayed in the DV on startup.
Wrote the RangeSet code to insert and delete to the selection
Added notification code to update the selection.
While testing the notification code I ran into a problem with the way collections are handling notifications. I need to coordinate with Ted and Andi to find a solution to the bug.