filter out bad characters when outputting strings in bestabs
filter out bad characters when outputting strings in bestabs

[r27649]

MatzeB/libfirm,davidgiven/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,8l/libfirm,libfirm/libfirm,davidgiven/libfirm,davidgiven/libfirm,MatzeB/libfirm,jonashaag/libfirm,jonashaag/libfirm,davidgiven/libfirm,davidgiven/libfirm,killbug2004/libfirm,killbug2004/libfirm,jonashaag/libfirm,MatzeB/libfirm,libfirm/libfirm,jonashaag/libfirm,killbug2004/libfirm,killbug2004/libfirm,8l/libfirm,8l/libfirm,davidgiven/libfirm,killbug2004/libfirm,MatzeB/libfirm,MatzeB/libfirm,jonashaag/libfirm,8l/libfirm,davidgiven/libfirm,libfirm/libfirm,jonashaag/libfirm,MatzeB/libfirm,8l/libfirm,libfirm/libfirm,libfirm/libfirm,killbug2004/libfirm,jonashaag/libfirm,8l/libfirm