TYPO3 Core

When profiling backend code (escpecially when there is templavoila involved) you'll notice that t3lib_div::xml2array() is one of the most "expensive" parts.

By introducing a cache this can by dramatically reduced (have a look at http://www.fabrizio-branca.de/fileadmin/statistics_xml2array.ods for some profiling statistics) in both backend and frontend.

I've implemented a first level cache (as a static variable) and a second level cache (using the new dbbackend), to prevent same xml string to be rendered more than once.

See patch

(issue imported from #M11260)