code: function streamHandler(stream) {
      return stream
        .pipe(plumber())
        .pipe(sourcemaps.init({loadMaps: true}))
        .pipe(sourcemaps.write('.', {includeContent: true, sourceRoot: '.'}))
        .pipe(gulp.dest(dest));
    }
docs: stream handler to apply further gulp plugins
  @param  {Object} stream  gulp file stream
  @return {Object}         processed stream