These instructions have been supplanted by an automated, scripted installer, which lives here:
https://github.com/mikepurvis/ros-install-osx
Please try it out, and file bugs as required. Feel free to browse past versions of this gist as a historical curiosity, but I won't be monitoring or supporting it any more.
also: if the "pip install -U ..." step fails, try first to do "pip install -U pip", then "pip install -U setuptools", and then repeat the pip install step with all arguments