Move circular GenomeDiagram feature labels outside sigil

This now matches the linear GenomeDiagrams, but is a break in
backwards compatibility, and may require us to review the default
spacing between tracks.
GenomeDiagram feature label_strand property
Mention moving circular GenomeDiagram labels in NEWS
Layout tweak for circular GenomeDiagram feature labels
Mention mmCIF changes in NEWS and DEPRECATED files

Documentation change only, no need for TravisCI [ci skip]
TravisCI doesn't have a fasttree package

$ sudo apt-get install clustalw clustalo fasttree | tail -n 2
E: Package 'fasttree' has no installation candidate
is only available from another source

(This wasn't breaking the builds, but did mean clustal wasn't
being installed and so those tests were skipped.)