/api/talks : +language (optional)
Merge pull request #213 from clacote/api-language

/api/talks : +language (optional)
/api/members works with /id (numeric only) or /login (elsewhere)
Validate Member.login : not numeric-only.
Merge pull request #214 from clacote/api-member-by-login

API : member details by login
Merge branch 'master' of git://github.com/cexbrayat/linkit
Profile page : display member's email for staff only