relax SVN archive

Partial fix for bug #21338 (https://gna.org/bugs/?21338) - the bad sRGB profile in some PNGs.

This is only partial as some files are still to be converted (the original Bruker logo, and the
16x16, 22x22 and 32x32 sized Bruker icons).

Modified sparky file to have no columns with intensity.

Copied sparky list to be modified for sparky file without intensity column.

Improved the DPL94 dispersion model description in the manual.

The average_intensity() dispersion function now accepts the offset argument.

This is for better support of combined offset and spin-lock varied R1rho-type data. The argument is
then passed into the find_intensity_keys() function.

Updated the news announcement link for relax version 3.1.1 at http://www.nmr-relax.com/download.html.

The correct link is https://gna.org/forum/forum.php?forum_id=2423.

Updated the relax API documentation at http://www.nmr-relax.com/api/3.1/ to version 3.1.1.

Updated the version number to 3.1.1 on the webpage http://www.nmr-relax.com/api/.

Updated the HTML version of the relax manual to version 3.1.1.

This is for http://www.nmr-relax.com/manual/index.html.

Updated the http://www.nmr-relax.com/download.html webpage for relax version 3.1.1.