Fix "Insert Zone to Bin" out point off by 1
If the user sets in=100, out=101 and select Insert Zone in Project Bin, the clip is created 1 frame longer than it should be. This is especially noticeable when creating a subclip when the out point is the last frame in the clip, resulting in a broken subclip that cannot be added to the timeline.
(The first commit only fixes bug 455883. The second commit is a much bigger commit that changes the handling of the out frame in the monitor to be consistent with the timeline.)
monitor.cpp doesn't seem testable without UI automation, but maybe someone has some ideas for testing?