Add missing <dt> in chat.tpl

Fixes #58
Set PAGE_TITLE after installation
Activate onlineList dashboard box upon installation
Disallow whispering of users that block one

Closes #61
Add language items for user group options

see #55
Add SECURITY_TOKEN to forms and bump WCF minimum version

see WoltLab/WCF@77329f86c560fe7490b0b2a02905301f6a33dfbd
Merge branch 'master' into attachments
Improve front end design of attachment