Merge branch '2.6.x' of http://git.centreon.com/centreon into 2.6.x

CHANGELOG

doc/en/conf.py

doc/en/guide_exploitation/02e.rst

doc/en/images/user/abootmenu.png

doc/en/images/user/adisplayicon.png

doc/en/images/user/arpminstall.png

doc/en/index.rst

doc/en/installation/01a.rst

doc/en/installation/downloads.rst

doc/en/installation/from_packages.rst

doc/en/installation/from_sources.rst

doc/en/installation/index.rst

doc/en/release_notes/centreon-2.6.1.rst

doc/en/upgrade/from_sources.rst

.../user/configuration/10advanced_configuration/01macros.rst

doc/en/user/index.rst

doc/fr/conf.py

doc/fr/faq/administration.rst

doc/fr/guide_exploitation/02e.rst

...ateur/configuration/10advanced_configuration/01macros.rst