Suffix "_outerXml" uses correct Handler now

A simple c&p mistake lead to the use of ContentXmlHandler instead of
ContentOuterXmlHandler. This commit fixes this issue.
Remove code for "#id"-handling.

Saxmir used to parse "#id"s with an extra chunk of code. With this
commit, the #ids will be converted to attribute matches. I.e.
"#foo" will become "[id=foo]"
ContentPlainHandler: Fix issue with doubled in multiple matches

ContentPlainHandler used to reuse a StringBuilder for every match. This
commit creates a new StringBuilder for every new match and prevents the
reuse without cleaning
ContentXmlHandler: Fix issue with doubled in multiple matches

ContentXmlHandler used to reuse a StringBuilder for every match. This
commit creates a new StringBuilder for every new match and prevents the
reuse without cleaning