Python Port quickstart

To run the Boost.Build Python port, follow these steps:

1. Get a fresh version of Boost.Jam from ​http://svn.boost.org/svn/boost/trunk/tools/jam and build it, by going to the "src" subdirectory and running ./build.sh --with-python=/usr. On Windows, use build.bat --with-python=<python-root>.
2. Get a fresh version of Boost.Build python port from ​http://svn.boost.org/svn/boost/branches/build/python_port
3. Go to the python/tests/bjam/make subdirectory and run bjam --build-system=pybb.