Webgui:	First try to implement session id and timeout
	* Uses Cookie (to much work to add sid to all menu entries [cache ...])
	* Disabled by default
	* Option on freetz Web config page to enable session id
	* will store passwords md5 hash
	* default pasword is "freetz", can be changed on web config page after enabling session ids
	* uses js md5 version from "blueimp" (https://github.com/blueimp/JavaScript-MD5)
	* might use avms md5 js in future (not available on old boxes), we'll have to check it during building the firmware


git-svn-id: file:///var/svn/freetz/trunk@12516 149334a1-2f27-0410-a3b9-fc62619ac1e6