code: public JSONArray jsonifyValues() {
          JSONArray jValues = new JSONArray();
          for (ValueEntry vEntry : values) {
              JSONObject o = new JSONObject();
              o.put("value",vEntry.getValue());
              o.put("timestamp",vEntry.getTimestamp());
              jValues.add(o);
          }
          return jValues;
      }
docs: Get an JSON array with values (along with their timestamps)
  
  @return array of values