code: String toRules(boolean escapeUnprintable) {
          int i;
          int count = ruleVector.size();
          StringBuilder ruleSource = new StringBuilder();
          for (i=0; i<count; ++i) {
              if (i != 0) {
                  ruleSource.append('\n');
              }
              TransliterationRule r = ruleVector.get(i);
              ruleSource.append(r.toRule(escapeUnprintable));
          }
          return ruleSource.toString();
      }
docs: Create rule strings that represents this rule set.