Fix related product rendering if nostock dont get rendered

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/commerce/branches/55612@84479 735d13b6-9817-0410-8766-e36946ffe9aa
Fix related produts rendering and fetching

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/commerce/branches/55612@84482 735d13b6-9817-0410-8766-e36946ffe9aa
Cleanup article type tca

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/commerce/branches/55612@84487 735d13b6-9817-0410-8766-e36946ffe9aa
Replace $this->cat usage with $this->category->getUid()

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/commerce/branches/55612@84488 735d13b6-9817-0410-8766-e36946ffe9aa