Now session support does not work with signed cookies

[fsateler]

The session "parser" in lib/user is just: this.user.session = nowjs.sessions[unescape(cookie)].

This doesn't work with signed cookies (or if one implemented encrypted cookies) since the session id is not the cookie string value.

Possibly nowJS should allow tu use a user-defined function to extract the session id from the cookies. Alternatively one could pass the secret to nowjs so it can validate the cookie is correctly signed.