Fix documentation, remove version cap on sphinxcontrib-bibtex

[Moritz-Alexander-Kern]

This PR removes the version cap on sphinxcontrib-bibtex==1.0.0.

Newer versions of sphinxcontrib-bibtex require the path to the .bib file to be specified in the configuration file for the documentation (conf.py).

• removed version cap for sphinxcontrib-bibtex
• added path to viziphant.bib file to conf.py
• removed html4 writer, since Issue Reference not rendered correctly in sphinx 2.2.0 sphinx-doc/sphinx#6705 (comment) is resolved and html4 is deprecated with newer versions of sphinx. Require Sphinx 1.6 deprecate html4 readthedocs/sphinx_rtd_theme#1091

See docs here: https://elephant-docs-development.readthedocs.io/en/fix-bibtex-contrib-version-cap/modules.html

[coveralls]

Coverage: 87.836% (+0.3%) from 87.493% when pulling 8d476b3 on INM-6:fix/bibtex-contrib-version-cap into 0896873 on NeuralEnsemble:master.

[Moritz-Alexander-Kern]

build wheels

[Moritz-Alexander-Kern]

With version 2.2.0 the reference style can be set:

To configure your referencing style, an optional config setting bibtex_reference_style has been added. If not specified, this defaults to the label style, which will use the label to format citation references, matching the referencing style as in previous versions. The other style currently available is author_year, for author-year style referencing.

See: https://sphinxcontrib-bibtex.readthedocs.io/en/latest/changes.html

[Moritz-Alexander-Kern]

For a sample of the new citation style, aswell as the new bibliography style, see:
https://elephant--523.org.readthedocs.build/en/523/reference/spade.html

Citation:

Bibliography:

[Moritz-Alexander-Kern]

build wheels

[Moritz-Alexander-Kern]

build wheels