Adjust LAYOUT to correctly state format of README.rst

In ~November 2009, we created README.mkd.

Later, we converted it to reStructuredText and renamed it.
No one fixed LAYOUT... until now!
Remark on origin of vendor/ trick
Encourage harder people to read README
Explain that this is Django-y
Bundle modules for local doc generation

This bundles Sphinx and dependencies so that users don't have to `pip
install Sphinx` or similar when generating documentation locally -- all they
have to do is run `python tools/render_docs.py` from the toplevel
directory.
Explain other bits of Django we use
Bundle dependencies
Merge pull request #154 from paulproteus/feature/longer-layout-file

Explain the LAYOUT of the code better
Merge pull request #155 from mandarg/bundle-sphinx

Bundle Sphinx and dependencies so documentation can be generated locally without needing additional module installs
Merge branch 'master' of github.com:openhatch/oh-mainline
make suggested changes to documentation.rst