Change to using a case insensitive tree map
make next HttpHandler final

This handler has no setNext(), so it is safe to make it final and remove volatile. Also sort the field initialization in both constructors the same. Add JavaDoc.

Signed-off-by: Bernd Eckenfels
Point to RFC 6454 in JavaDoc

Signed-off-by: Bernd Eckenfels
Fix checkstyle