#1793 Doubling note length increases segment length by 7+ measures

[musewhirl]

Increasing the size of a note, within the limits of the large measure of a segment causes that segment length itself to increase...in some cases by an unreasonable amount.

Steps to reproduce:

1. Create one-measure segment at measure 6
2. Open MatrixEditor on segment
3. Set default Grid size 1/16
4. Create a note 1/16 at a position one eighth before end of measure
5. Select note

Now Attempt to increase the note size by any of the following:

• Drag note length to increase to 1/8: segment size is unaffected. Undo will undo note size.
• CTRL-SHIFT-H: segment size increases to 7 and 7/8 measures. Undo with undo both note size and segment length.
• Menu option Adjust/Rescalse/Double: segment size increaes to 7 and 7/8 measures. Undo with undo note size and segment length.
• Menu option Adjust/Rescalse/Stretch or Squash and select a new note size of 1/8: segment size increases to 1 and 1/8 measures. Undo only undoes note size, not segment length.

I can open a separate bug for the following if you wish, but:
That Stretch or Squash note dropdown has no scrollbar, although the mouse wheel reveals lower items. If the mouse wheel is minimally scrolled (one click in my case), a few more items show up, but then simply moving the mouse to the end of that dropdown, without using the wheel) causes all remaining items to automatically scroll up until the last item shows. I don't think it's supposed to behave like that with or without a scrollbar. And besides, when fully scrolled down, a minimal mouse wheel scroll up does not result in the opposite behavior.

[Philip Leishman]

Yes RescaleCommand had a rather dodgy calculation of the end time. No not dodgy - downright wrong!
See merge request.
The note dropdown has a scrollbar for me. What style are you using ?