[TASK] Modify SQL query calls for TYPO3 CMS 6.1 compatibility

mc_googlesitemap uses hacky and direct MySQL queries to fetch
accordant data. Since the database handling has been changed in
TYPO3 CMS 6.1 and furthermore the PHP extension "mysqli" is used,
the elderly queries in mc_googlesitemap don't work anymore.

This change switches to TYPO3_DB and thus used the database API
of TYPO3 - which always should be used...

| This change thankfully has been sponsored by
| Silke Arend (a7digital GmbH), see http://www.a7digital.de
[TASK] Set version to 0.5.0 and state to beta