[BUGFIX][!!!] #53287: Cannot mix TCA and non TCA-based additional parameters

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/direct_mail_userfunc/trunk@81173 735d13b6-9817-0410-8766-e36946ffe9aa
[TASK][UX] #53288: Rename "User function" and "itemsProcFunc"

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/direct_mail_userfunc/trunk@81174 735d13b6-9817-0410-8766-e36946ffe9aa
[TASK][UX] Change extension's title

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/direct_mail_userfunc/trunk@81175 735d13b6-9817-0410-8766-e36946ffe9aa
[TASK] Better extension description

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/direct_mail_userfunc/trunk@81176 735d13b6-9817-0410-8766-e36946ffe9aa