limit variable scope
add itsdangerous' URLSafeTimedSerializer parser

Parse and return serialized datastructure, if not expired yet. Does not
validate the signature.

    lib.itsdangerous("WzIsIjg1MTM2Yzc5Y2JmOWZlMzZiYjlkMDVkMDYzOWM3MGMyNjVjMThkMzciXQ.BrF35w.IoiMIKcqb2Dgy4Gq7uYXSojcVSM"));
add dummy option for auth
max_age is optional now
Use auth cookie in the client