Adds `action=firstNew` parameter to unread conversation links in drop down

This way, the user can directly read the unread messages.
Clean up package
Added validateMessage()
Using WCF.UserPanel
Notification system overhaul
Merge branch 'master' of github.com:WoltLab/com.woltlab.wcf.conversation
Added conversation log
Added object type for modification log
Added option and modification log for 'addParticipants'
Fixed missing 'start conversation' button
Merge branch 'master' of github.com:WoltLab/com.woltlab.wcf.conversation
Add titles to feed

https://www.woltlab.com/bugtracker/index.php?page=Bug&bugID=2165
Replace &bdquo; &ldquo; &rdquo; with UTF-8 characters
Replace &bdquo; &ldquo; &rdquo; with UTF-8 characters - finally
Use english quotes in en.xml
Major API overhaul
Add missing requirement on com.woltlab.wcf.bbcode
Major API overhaul
Add missing requirement on com.woltlab.wcf.user
Merge branch 'master' of
github.com:WoltLab/com.woltlab.wcf.conversation