Fix charset setting for emails set in deferred mode

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/sr_sendcard/trunk@84413 735d13b6-9817-0410-8766-e36946ffe9aa
Update version to 3.1.0

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/sr_sendcard/trunk@84415 735d13b6-9817-0410-8766-e36946ffe9aa