Adding regex flags

PREG_OFFSET_CAPTURE is a very important flag
Update textOptionType.tpl to validate minlength an maxlength
Merge pull request #1154 from PhrozenByte/enhancement/RegexFlags

Adding regex flags
Optimize updating user group options
Improve clearness in Regex
Properly save status code in HTTPRequest
Added method to get multilingualism status
Merge branch 'master' of github.com:WoltLab/WCF