Revision history for Perl extension GnuplotIF.

1.0  Thu Jul 28 11:00:14 2005
  - original version; created by h2xs 1.23 with options
  -XA -n GnuplotIF

1.1  Aug 27 2006
  - method gnuplot_set_plot_titles added (thanks to Stephen Marshall)

1.2  Jun 06 2007
  - tests improved

1.3  Oct 13 2007
  - Module no longer dies if no display is available (allows batch mode). 
  - Method gnuplot_plot_xy_style (thanks to Georg Bauhaus)

1.3.1  Nov 10 2007
  - All prints to pipes will be checked.
  - New test: 8 pipes open in parallel.

1.4  Nov 28 2007
  - Plot window can survive after gnuplot exits.
  - Plot can be stored to a script file instead of beeing executed immediately.
  - New method gnuplot_plot_3d makes 3-D-plots from arrays.
  - New method gnuplot_hardcopy writes a plot into a file for printing.
  - New method gnuplot_restore_terminal restores terminal settings before the
    last hardcopy.

1.5  June 11 2008
  - Method gnuplot_plot_many() and gnuplot_plot_many_style for x-y-plots not
    sharing an x-axis.
  - Most method calls can now be chained (thanks to Bruce Ravel for both).

1.6  March 3 2011
  - gnuplot_pause() not working as advertised.
  - New constructor argument 'plot_also': write all plot commands to a file, in
    addition show the plots.

1.7  June 3 2011
  - Windows support  (thanks to Bruce Ravel).

1.8  January 2 2016
  - Fixes concerning pathes with spaces (thanks to Bruce Ravel).
  - Fix for situations where the user does not have write privilege for the
    current working directory (thanks to Bruce Ravel).