- 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
setting headers to allow browser to cache the file until it's etag containing the creationdates of the used langfiles changes
--> et2 can now use egw_lang object to translate labels, options, ...