Better pattern matching for typo3 login

Follow-up of: https://github.com/sullo/nikto/pull/160

Just tested against TYPO3 4.5.x and 6.2.x which contains this string in the index.php. The live demo of TYPO3 available here:

http://introduction.cms.demo.typo3.org/typo3/

contains also the matching:

    <!-- TYPO3 Script ID: typo3/index.php -->