Handle null ups and downs in evolutions gracefully
Mention session.maxAge in the documentation

There is a way to set the maximum age of the session cookie but the documentation did not point it out.
Merge pull request #3355 from urcadox/patch-1

Mention session.maxAge in the documentation
Merge pull request #3033 from gmethvin/null_evolutions

DB evolution: Application stops working if '# --- !Downs' part does not exists or empty