Added new session configuration directives.

# Sascha, please document them here.

php.ini-dist

@@ -277,8 +277,10 @@ session.use_cookies = 1             ; whether to use cookies
 session.name = PHPSESSID            ; name of the session
                                     ; is used as cookie name
 session.auto_start = 0              ; initialize session on request startup
-session.lifetime = 0                ; lifetime in seconds of cookie
+session.cookie_lifetime = 0         ; lifetime in seconds of cookie
                                     ; or if 0, until browser is restarted
+session.cookie_path =               ;
+session.cookie_domain =             ;
 session.serialize_handler = php     ; handler used to serialize data
                                     ; php is the standard serializer of PHP
 session.gc_probability = 1          ; procentual probability that the 
@@ -287,3 +289,6 @@ session.gc_probability = 1          ; procentual probability that the
 session.gc_maxlifetime = 1440       ; after this number of seconds, stored
                                     ; data will be seen as 'garbage' and
                                     ; cleaned up by the gc process
+session.extern_referer_check =      ;
+session.entropy_file =              ;
+session.entropy_length = 0          ;