proper error messages in query editor frontend

  outline: none;

}

#query_editor_error {

  display: none;

  padding: 7px;

  font-family: monospace;

  background: #ecc;

  border: 1px solid #f88;

}

#query_editor_error.visible {

  display:block;

}

.swatch {

  width: 10px;

  height: 10px;

    }

    var query = editor.getValue();

    if (query.length == 0) {

      return;

    }

    var xmlHttp = null;

    xmlHttp = new XMLHttpRequest();

    xmlHttp.open("POST", "/query", false);

    xmlHttp.send(query);

    console.log(xmlHttp.responseText);

    var response = JSON.parse(xmlHttp.responseText);

    var error_div = document.getElementById("query_editor_error");

    if (response.status == "success") {

      error_div.className = "";

    } else {

      error_div.className = "visible";

      error_div.innerHTML = response.error;

    }

  };

  var renderQueryView = function() {

        navbar +

        "<div id='query_editor'>" +

          "<textarea id='query_editor_textarea'></textarea>" +

        "</div>";

        "</div>" +

        "<div id='query_editor_error'></div>";

    editor = CodeMirror.fromTextArea(

        document.getElementById("query_editor_textarea"),

    stage/src/fnordmetric/util/format.cc

    stage/src/fnordmetric/util/inputstream.cc

    stage/src/fnordmetric/util/outputstream.cc

    stage/src/fnordmetric/util/jsonoutputstream.cc

    stage/src/fnordmetric/util/threadpool.cc

    stage/src/fnordmetric/util/runtimeexception.cc)

  addHeader("Content-Length", std::to_string(body_.size()));

}

void HTTPMessage::clearBody() {

  body_.clear();

}

std::unique_ptr<util::InputStream> HTTPMessage::getBodyInputStream() const {

  return util::StringInputStream::fromString(body_);

}

  const std::string& getBody() const;

  void addBody(const std::string& body);

  void clearBody();

  std::unique_ptr<util::InputStream> getBodyInputStream() const;

  std::unique_ptr<util::OutputStream> getBodyOutputStream();