mostly Valentin Todorov:  fix the exactfit case "MAD=0" -> new exactfit code = 3

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/robustbase@649 694ef91d-65df-0310-b7bb-92e67a308ead
cosmetic

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/robustbase@650 694ef91d-65df-0310-b7bb-92e67a308ead