First docs draft
Merge branch 'master' into docs
[#39] New docs

Completely revised and restructured docs to be built with Sphinx.
Structured in logic areas, with a big cleanup and nice formatting.
Revised install instructions.

Added the okfn-sphinx-theme submodule to have a consistent look and feel
with the core CKAN docs, although core docs are using an older revision.
[#39] Add doc-requirements.txt
[#39] Update submodule path
[#39] Update README to point to new docs
[#39] README tweaks
Merge branch 'docs'