[Doc] Bug fix on the incompatible sphinx bibtex version. Constrain to the right version.
#recommonmark
#Handle references in bibtex format
-sphinxcontrib-bibtex
+sphinxcontrib-bibtex<2.0.0
#Work-around bug "AttributeError: 'Values' object has no attribute 'character_level_inline_markup'" with docutils 0.13.1
#See:
