[Kst-plot/kst] 50b599: Don't crash on an empty file.

[netterfield]

  Branch: refs/heads/master
  Home:   https://github.com/Kst-plot/kst
  Commit: 50b5995e35bbcf527b94b40de5b3c4db0cddf73f
      https://github.com/Kst-plot/kst/commit/50b5995e35bbcf527b94b40de5b3c4db0cddf73f
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2021-07-07 (Wed, 07 Jul 2021)

  Changed paths:
    M devel-docs/BugsAndFeatures
    M src/libkstapp/commandlineparser.cpp

  Log Message:
  -----------
  Don't crash on an empty file.

This stops the crash, but no warning is generated that
the field might not be found, and the field suddenly existing
doesn't allow the kst session to start working.

So maybe we can do better.


  Commit: a66bbdec3728d49d35b6371e61384b6b09365892
      https://github.com/Kst-plot/kst/commit/a66bbdec3728d49d35b6371e61384b6b09365892
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2021-07-08 (Thu, 08 Jul 2021)

  Changed paths:
    M devel-docs/BugsAndFeatures
    M src/libkstapp/commandlineparser.cpp
    M src/libkstapp/commandlineparser.h

  Log Message:
  -----------
  Exit with an error if an empty file is opened from the command line.

The old behaviour was to crash.


  Commit: 0e61cdde70365cfcf45deac51c7bcceb01d9b2f6
      https://github.com/Kst-plot/kst/commit/0e61cdde70365cfcf45deac51c7bcceb01d9b2f6
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2021-07-09 (Fri, 09 Jul 2021)

  Changed paths:
    M src/libkstapp/commandlineparser.cpp
    M src/libkstapp/commandlineparser.h

  Log Message:
  -----------
  Add command line options to control legends.

--showLegend, --hideLegend, and --autoLegend


Compare: https://github.com/Kst-plot/kst/compare/254ee25e7a57...0e61cdde7036