4.4.11 docs fixes

This PR rebases some fixes from dev_5_0 and deletes a link to github content which doesn't exist since the re-organisation of Bio-Formats (I haven't replaced it as no-one should really be reading the BF developer docs on the 4.4 branch any more anyway). Just so we can release 4.4.11 with a green docs build for completeness.

Should make http://ci.openmicroscopy.org/view/Docs/job/BIOFORMATS-4.4-merge-docs/ green again.