Commit Release 1.81 (biopython#4233)

* Disable part of qblast test_short_query.

* Updated list of contributors for 1.81

* Biopython 1.81

* Fix docstrings for Sphinx API docs to succeed

* Add convenience clean methods to Makefiles to simplify building/testing.

Version bump for v1.80

Fix LaTeX syntax to allow documentation to build.

Ready for Biopython 1.78

Update Tutorial with links to 1.77 api docs (biopython#2903)

Changed links from API docs built with epydoc to those built with Sphinx

Version bump for v1.76

Revert adding EMBL-CDS from UniProt (biopython#2310)

This reverts commit 3b46a06
and the associated acknowledgements.

Sadly we don't (yet) have consent for the dual licensing, my
mistake in not catching this while reviewing the pull request.

Double backticks for RST markup

Avoid using single backticks (other than RST links).

Call this Biopython 1.73

Call this Biopython 1.72