code: public JSONBuilder quote(String value) {
          _sb.append('"');
          for (int i = 0; i < value.length(); ++i) {
              char c = value.charAt(i);
              switch (c) {
              case '"':
                  _sb.append("\\\"");
                  break;
              case '\\':
                  _sb.append("\\\\");
                  break;
              default:
                  if (c < 0x20) {
                      _sb.append(CTRLCHARS[c]);
                  } else {
                      _sb.append(c);
                  }
                  break;
              }
          }
          _sb.append('"');
          return this;
      }
docs: Quotes properly a string and appends it to the JSON stream.
  
  @param value - a liternal string to quote and then append
  @return the JSONBuilder itself