Minor rST tweaks
Revert "Revert "[#3,theme][m]: switch to standard okf sphinx theme - fixes #3."" - thereby reapplying new theme.

This reverts commit cfcd5c30a8febb5066fd70efd8ed0911a56a14dc.
[#3,theme][s]: some fixes for new theme.

* reinstate edit on github link lost in first pass
* require sphinx 1.2b3 (provides recent jquery plus respects :hidden: toc directive for generating global toc in sidebar)
Set default highlight language to 'none'

This prevents somewhat spurious highlighting when inlining non-python
examples. You can still always set language for a block with, e.g.

    .. highlight: python
Don't show build version

This isn't really relevant for the Ops Manual
Merge branch 'okfn-theme'

Fixes #4.