Add abbreviations and links examples.

Internal and external links to 'Python' and 'matplotlib' Sphinx documention
was added. See the 'intersphinx_mapping' variable in 'doc/source/conf.py'
for further information.

	modified:   doc/source/api/titi_module.rst
	modified:   doc/source/conf.py
	modified:   doc/source/intro.rst
	modified:   lib/toto/titi.py