Auto-login through client certificate

[GoogleCodeExporter]

Brief description of the enhancement:
Automatic login for client using certificates. Jardin could retrieve client 
informations from a client certificate and so bypass login window.

Detailed use-case:
A client installed a client certificate in his browser.
The client tries to access Jardin.
The server checks whether the client is using a client certificate.
The server checks and retrieve client information from the certificate.
If the certificate is valid and all client information are correct, the 
server bypass login window and starts a session for the certified client.

Original issue reported on code.google.com by gpantane...@gmail.com on 17 Mar 2010 at 3:57