issue #97 modification of session timeout mechanism

Now session timeout worked =)
And it is described in config file and no possibility to set it for each user differently.
Furthermore added setting of session store path.

config.sample.php

@@ -9,7 +9,7 @@
 // session store configurating
 
 // Timeuot of session in seconds
-ini_set('gc_maxlifetime', 60*60*3); //3 hours
+ini_set('session.gc_maxlifetime', 60*60*3); //3 hours
 
 // this defines, where session files will be stored.
 // it is important in this case: http://php.net/manual/en/session.configuration.php#ini.session.gc-maxlifetime