[Bug 4919] Clean up the registration form code.

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/seminars/trunk@83228 735d13b6-9817-0410-8766-e36946ffe9aa
[Bug 4919] Feature: Make the fields on the confirmation page extensible

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/seminars/trunk@83233 735d13b6-9817-0410-8766-e36946ffe9aa
Bump the version number to 0.9.80.

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/seminars/trunk@83234 735d13b6-9817-0410-8766-e36946ffe9aa