Automatically inserts a user-provided amount of markers.
If a time range is selected, this range is used and markers are inserted beginning with the start of the time range.
If no time range is selected, then it finds the last piece of recorded media and inserts markers beginning at 0 and ending before the end of the latest recorded media item.
If anyone has requests or suggestions, feel free to leave a comment. I don't mind tweaking a bit. I'm thinking about making it work for a selected media item (or a few selected media items) as well as selected tracks...