update git submodule to reference latest commit at new repo
fix gendocset.py to work with Github repo format
add .gitignore for generated files and *~
add setup scripts and Make rules for setup/generation

Previously the build procedure was documented via comments in
gendocset.py.  This CL automates much of the prep & build.  The
automated version now also uses virtualenv and pip, in line with modern
Python dev practices.
Update packaged docset.tgz

Note that this was made with the package make rule.
Merge branch 'update-package-20140612'