improve logging code (refactor handling of ANSI codes)
improve logging code (refactor handling of ANSI codes)

(issue #893)

moyogo/fontbakery,graphicore/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,googlefonts/fontbakery