[Kst] [Kst-plot/kst] d41916: Save current tab in .kst file.

[Barth Netterfield]

  Branch: refs/heads/master
  Home:   https://github.com/Kst-plot/kst
  Commit: d4191686295916c0f0ae9196f4e62e827d9c09d7
      https://github.com/Kst-plot/kst/commit/d4191686295916c0f0ae9196f4e62e827d9c09d7
  Author: Barth Netterfield <netterfield at astro.utoronto.ca>
  Date:   2015-02-23 (Mon, 23 Feb 2015)

  Changed paths:
    M src/libkstapp/document.cpp

  Log Message:
  -----------
  Save current tab in .kst file.

Save the current tab when saving a kst file.
Additionally, when loading an older kst file
which hasn't save the current tab index, start
with tab 0 (rather than the last tab).