Fix #882: add coloring of multihardlinks filenames; do not ignore "mh" in LS_COLORS

[mstelmas]

This fixes issue 882

It adds coloring of files with multiple hard links using the default color (red on black; any suggestions for a better pick?) or the one specified via the "mh" property in LS_COLORS. The behavior seems consistent with the one provided by the 'ls' utility.