Merge pull request #23 from mespeche/master

Fix page.description variable (for meta tag description) bug
Merge pull request #24 from mespeche/master

Adding of willdurand plugin Anchorify
change submodule protocol
update address create/update events
add info about address removal
add cateogry events
add before/after on category object
create hook documentation and fix contribute part
complete hook part
change syntax
update how to install thelia using only composer
update franch doc
change php installation for mac os
change memory_limit value