User/group names can include characters that maybe should be filtered out such as quotes and more

[jkeltz]

Issue Description

I didn't include a fix for this because I'm not sure whether this is a bug or not. Should admins really be able to include such things as quotes, etc. in usernames or group names? Probably not.. probably need to implement better checking in the future...

[einhirn]

The user/group names are filtered through the auth-plugin's cleanUser/cleanGroup functions - if they don't throw these characters out, they'll probably be ok!? Even if one were to change the auth backend later, the cleaning happens before comparison etc. so worst case would be that someone loses access because of characters that are filtered now.

As for display of the values the plugin saved, I seem to remember that everything gets htmlspecials treatment or something like that before being sent to the browser...