code: function cleanOutputDir(done) {
  			var htmlDemoFileMask = path.join(o.destCss, o.fontBaseName + '*.{css,html}');
  			var files = glob.sync(htmlDemoFileMask).concat(wf.generatedFontFiles(o));
  			async.forEach(files, function(file, next) {
  				fs.unlink(file, next);
  			}, done);
  		}
docs: Clean output directory
  
  @param {Function} done