[Kst] [Kst-plot/kst] 646b4e: Add shortcuts for zooming in (+) and out (-).

[Barth Netterfield]

  Branch: refs/heads/master
  Home:   https://github.com/Kst-plot/kst
  Commit: 646b4eccb21e80963115979e72da5f18846e28ec
      https://github.com/Kst-plot/kst/commit/646b4eccb21e80963115979e72da5f18846e28ec
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2016-03-29 (Tue, 29 Mar 2016)

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

  Log Message:
  -----------
  Add shortcuts for zooming in (+) and out (-).


  Commit: 55359bdc2096df2160b7f63cedd5207728be22ee
      https://github.com/Kst-plot/kst/commit/55359bdc2096df2160b7f63cedd5207728be22ee
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2016-03-29 (Tue, 29 Mar 2016)

  Changed paths:
    M src/libkstapp/plotrenderitem.cpp

  Log Message:
  -----------
  Don't rezoom manually zoomed empty plots.

When adding a new curve to an empty plot, don't
use auto zoom if the plot had already had its
range set manually.


Compare: https://github.com/Kst-plot/kst/compare/adf103176827...55359bdc2096