Added option to obtain thumbnail dimensions

See
http://beta.woltlab.com/index.php/Thread/4094-Dateianh%C3%A4nge-Vorschau-besser-skalieren/
Fixed typo
Properly cloning i18n style description
Fixed retard protection
Updating minified JavaScript files
Fixed user storage reset/update race condition
Merge branch 'master' of github.com:WoltLab/WCF
Fixed attachment import issue
Merge branch 'master' of github.com:WoltLab/WCF
Fixed use order
Fixed XSS vulnerability
Merge branch 'master' of github.com:WoltLab/WCF
Renamed option
Merge pull request #1538 from SoftCreatR/AttachmentActionMod

Add option to obtain thumbnail dimensions
Fixed wrong redirect after login and potential security issues
Updating minified JavaScript files
Small style optimization
Merge branch 'master' of github.com:WoltLab/WCF
Fixes name of edited group in group dropdown menu
Fixes typo