processed bycodes for character entity references (with title, named, hex,
and dec version) -> mapping is not unique though...

.fix_character_entity_references() function that can map to any one of the
modes (named, hex, dec) -> rather slow due to double for() loop...



git-svn-id: svn://svn.r-forge.r-project.org/svnroot/exams@636 edb9625f-4e0d-4859-8d74-9fd3b1da38cb