code: function _fill(string, length, c) {
          if (c === undefined) {
              c = " ";
          }
          while (string.length < length) {
              string += c;
          }
          return string;
      }
docs: Fill a string to the given length (used for debug output)
  @param {string} source string
  @param {integer} length
  @param {char} fill character