don't display outedge warnings for blocks
don't display outedge warnings for blocks

[r15269]

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