r51526: fix wrong parameter order in call to egw.config() by removing it completly, as session is anway instance specific (and due to wrong order returned key was always empty)
r51527: garding againts data set in egw object by reference from an other window, causing data to be inaccessible in IE after window closes
r51528: removing an other unnecessary egw_info[flags][js_link_registry]=true
- user.php was not reloaded if (session-)preferences changed eg. language via select-box in login, because we used Expires header, but did not force a different url
- (user|config|images).php now has etag on url, to force reload by browser as we use an Expires header (changed images still need Admin >> clear cache to rebuild image cache)
- preferences are now loaded via a cachable GET request
