TVA (#39) Improve the width of the SCT columns when using multiple sheets.
Bug Number: n/a
Release notes (y/n): Yes
For Release Nums: 7.1

The introduction of "SCT Sheets" in RiverWare 7.0 had some undesirable 
behaviors with respect to Slot and DateTime column width stability and 
persistence, e.g. when switching from one SCT sheet to another. Note that 
the various sheets in an SCT differ in only the set of series slots presented 
in the SCT "Series" tab, but all have the same timestep configuration (time 
range and timestep size). In the horizontal time axis orientation, columns are
timesteps; in the vertical time axis orientation, columns are series slots.

This work included the following enhancements:

(1) Time column widths applied to horizontal-time SCT views are now preserved
 ON A PER SHEET BASIS within the RiverWare session. These widths, however, 
are not preserved in the SCT configuration file. The first time a horizontal-
time SCT view is presented, the time columns are adjusted to the column 
content (and this applies on a per-sheet bases -- see the next item).

(2) The following column width adjustment operations (accessible as both menu 
items and toolbar buttons), now operate on only the slot columns in the 
current SCT Sheet. This is relevant for both axis orientations, i.e. on both 
series slot columns and DateTime columns.

(a) Resize Columns: Set All to Selected Column Width
(b) Grow Columns: Fit Data
(c) Resize Columns: Fit Data
(d) Resize Columns: Fit All (header and cell data width).

TECHINCAL

This time column width session persistence makes use of these two new maps 
in the SctConfig class:

  // Sheet-Specific Applied Time Column Widths
  mutable QMap<QString,IntSeries*> _noAggTimeDataSheetColWidthSeriesMap;
  mutable QMap<QString,IntSeries*> _aggTimeDataSheetColWidthSeriesMap;

... these QMaps are indexed by the Sheet Label text.  Associated with each 
sheet is a dynamically allocated IntSeries -- that is, a Series<int> instance.
There is one of these maps for each of the two horizontal time SctViews: 
Aggregated and Non-Aggregated.

The timestep size and time range of these series is set by this method:
  void SctModelData::resyncSctConfigTimeColWidthSeries (bool agg);

Access to these IntSeries is done via these methods:
  void SctTableModel_THorzStd::recordColWidth (int col, int newWidth);
  void SctTableModel_THorzAgg::recordColWidth (int col, int newWidth);
  int SctTableModel_THorzStd::recordedColWidth (int col) const;
  int SctTableModel_THorzAgg::recordedColWidth (int col) const;

An initial iteration of the time column development work addressed the 
following undesirable behavior: switching to a different SCT Sheet was 
unnecessarily resetting the time column widths to the default width.  
This was caused by the fix to Gnats 5877 ("SCT display issues when removing 
a slot", Jan 2017) which was reported with RW 7.0.1 (after the upgrade from 
Qt 4.8.5 to Qt 5.5.1).  The part of that fix which caused this problem was 
unnecessary for vertical time SCTs.  See the change in method: SctView::
updateSerSlotTabSlotVis().