Given an http or https URL with user and password, URL-decode the user
and password info before base64 encoding it for the Authorization header.
Also:
 - eliminate the COOKIE_MAX_LEN constant (if they can fit it on the command
   line or in their environment, surely we can malloc the base64 version)
 - rename the variable with user:pass from "cookie" to "credentials"
 - empty password isn't an error
 - add a boolean ishttpurl so that we don't have to do strcmps on the schema
   that we just set
 - when looping across multiple ftp:// urls on the command line, don't
   leak the username/password memory

problem noted by Se'bastien Marie (semarie-openbsd (at) latrappe.fr)
Assume we have getfsstat(); simplify the interface to the *mountent()
wrappers