SCT: Better Sheet support for "Go To" menu [1]
Bug Number: n/a
Release notes (y/n): No (not yet)
For Release Nums: 7.2

See original analysis.  This is am implementation (with a few nuances) of 
Proposal 2:
http://cadswes2.colorado.edu/~philw/2017/SCT/GoToMenu/SctGoToMenuWithSheetSupport-Analysis.html

If the SCT doesn't use "Sheets", then the "Go To" menu is built as it had 
been in prior RiverWare versions.  That is, if there are fewer than a certain 
number of dividers* in the SCT, the "Go To" menu has a single single menu -- 
with items for each divider (with the text either coming from the divider -- 
or, if that is blank, the text of the subsequent slot item).  If there are 
more than that number of dividers, a two-level cascaded menu is built, with 
just numbered high-level items.

  http://cadswes2.colorado.edu/~philw/2017/SCT/GoToMenu/Ref/TvaGreg-SctGotoMenu1b.png

*This number (SCT divider count) had been 20, but was bumped up to 22 for 
better treatment of an established TVA SCT.  See this symbol in QtSCT/
SctDialog.cpp:

  static const int MAX_ITEMS_PER_JUMP_MENU (22);

However, with this commit, if the SCT DOES use "Sheets", the top-level items 
are based on the Sheet names.  Sheets which lack any "internal" Slot Dividers 
are presented as just a top-level menu item.  Sheets having "internal" Slot 
Dividers are presented as a submenu of items for those dividers, with an 
initial "Start of Sheet" item to go to the top row (or leftmost column) of 
the sheet.  Actually, if the number of dividers within a sheet exceeds the 
"MAX_ITEMS..." value (see above), then multiple submenus are presented for 
that sheet (See the top two panels in the first image below).

These two screenshots demonstrate the result with actual production TVA SCTs 
(one with a slight modification, to test one of the nuances described above):

  http://cadswes2.colorado.edu/~philw/2017/SCT/GoToMenu/2017-06-19/SctGoToMenus1.png
  http://cadswes2.colorado.edu/~philw/2017/SCT/GoToMenu/2017-06-19/SctGoToMenus2.png

---