Merge branch 'extractcalex': correction, new mode, new plot script

This is a legacy commit from before 2015-03-01.
It may be incomplete as well as inconsistent.
See COPYING.legacy and README.history for details.

sg056iter.gpt:
  corrected calculation of poles

calexiterextract.awk:
  implemented new mode "persearchrange"

sg056resp.gpt:
  new script to plot response function

SVN Path:     http://gpitrsvn.gpi.uni-karlsruhe.de/repos/TFSoftware/trunk
SVN Revision: 5502
SVN UUID:     67feda4a-a26e-11df-9d6e-31afc202ad0c