TYPO3 Core

The removeXSS-script used had some lacks. It replaced tags in normal text which prevents most from using this script.

Jigal did some improvements and i reformatted to CGL and tested.
These changes are done:

• bugfixes in regexps
• optimizations
• quickscan for keywords to speed up the function when no potential threats
• regexps specific for different type of keywords to reduce false positives
• configurable "tag replaceString"

(issue imported from #M9778)