I have posted MASON 15 to the website. Go grab it!
This is the code which was on the SVN repository while writing the manual, and has a great number of changes from MASON 14, many of them NOT backward compatible, but requiring relatively small changes. I decided to do this one-time-only because of the manual.
I've also revised the libraries to the ones required by MASON 15. Be sure to download those and update appropriately.
I have also posted new versions of the socialnets and physics2d to ones compatible with MASON 15. Hope everything goes smoothly. Sometime soon (I hope) we should have a new tarball of Geomason compatible with MASON 15 as well -- it's just a matter of posting it to the site.
Last but not least, the manual has been posted to the site.
PLEASE write to the mailing list if you find any errors, or if you have difficulty upgrading, and I will be glad to help.