Merge pull request FriendsOfSymfony#162 from zocimek/master

fixed data transformer for null values

Add a note that the documentation is currently being rewritten.

Merge pull request FriendsOfSymfony#130 from toinouu/patch-1

Update validation.xml

Merge pull request FriendsOfSymfony#64 from zocimek/master

Multiple recipients support

Merge pull request FriendsOfSymfony#66 from gimler/patch-1

fix FriendsOfSymfony#62