Sphinx2

Except for the last 2 commits, these are all changes / improvements to the ags.tex file. I cannot build the output from it, since I cannot compile tex2rtf at my system, so I my have broken the .tex file. Please verify.

Commit 55602ec50a2ca5360f1c59ce1eb33633e1ca2719 adds the same manual, but in Sphinx format. This is a text format, with markup in plain ascii. The tool can produce a multitude of output format, including html and windows help files. It is an industral-strength tool, docs.python.org is generated with it, containing all documentation for every Python version. The .RST files are sources, other things are build files. I added a short README.txt as well explaining how to build HTML and Windows HTML Help files.

Commit cf902739fd37ab469049992c020799ab166aa7a adds a Python 3 conversion script, and a patch file for the last changes that the conversion script missed. You don't actually need these files, but they may be useful perhaps.