Merge pull request #256 from StefTweet/2.3

Finish update references @ 04 06 2013
[Cookbook] update assetic part
Update references

with last commit beetween 30 05 and 04 06
Merge remote-tracking branch 'origin/2.3'
Correct some errors in Sphinx
Merge branch '2.3'
Merge pull request #259 from StefTweet/master

Up to date the references Section
Merge pull request #258 from tyx/cookbook/assetic

Cookbook/assetic