add page language overlay handling for canonical tag

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/mfc_canonical/trunk@76304 735d13b6-9817-0410-8766-e36946ffe9aa
update version to 1.5.0

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/mfc_canonical/trunk@76309 735d13b6-9817-0410-8766-e36946ffe9aa