[documentation] improve Sphinx support
Wrong default SonataAdminBundle layout name

It bring up an error in my project, but it seems like too easy...
SonataAdminBundle views : https://github.com/sonata-project/SonataAdminBundle/tree/master/Resources/views
Merge pull request #51 from lologhi/patch-1

Wrong default SonataAdminBundle layout name
Merge branch 'sonata-project/master'