* Only set the session_id if it differs to the cookie value (session_id($id) always sends a cookie in session_start() and SID is always set, so we do this only when needed)
* Don't add the session ID in the PayPal Login returnurl
If SESSION_FORCE_COOKIE_USE is enabled and the first request is made to login.php, no cookie is found (but is set) so perform another check before redirecting directly to the cookie_usage.php page
Merge pull request #46 from haraldpdl/session

Session Improvements