doc: Fix short documentation header line.
doc: Add newlines to fix Sphinx warnings.

reST requires newlines between blocks that change indentation. Sphinx
doesn't seem to mind, mostly, but it produces a lot of warnings if
they're missing.
doc: Add missing toctree entries.
Merge pull request #1355 from QuLogic/doc-updates

Documentation updates
The dead simplest lower the bar, move the bar, trip over the bar, pyugrid/iris integration.
Fix test failures and add trivial test assertion.
Merge pull request #1359 from rhattersley/ugrid

(Highly!) experimental UGRID support