bump arduino-json to 5.6.7

.travis.yml

@@ -22,7 +22,7 @@ install:
 - ( cd ${ARDUINO_ESP8266_ROOT}/tools && python get.py )
 before_script:
 - mkdir -p ${ARDUINO_HOME}/libraries
-- ( cd ${ARDUINO_HOME}/libraries && ln -s ${TRAVIS_BUILD_DIR} firebase-arduino && ln -s ${TRAVIS_BUILD_DIR}/src/third-party/arduino-json-5.3 ArduinoJson && ln -s ${HOME}/SoftwareSerial ./ && ln -s ${HOME}/Adafruit_NeoPixel ./ && ln -s ${HOME}/Adafruit-GFX-Library ./ && ln -s ${HOME}/Adafruit_SSD1306 ./)
+- ( cd ${ARDUINO_HOME}/libraries && ln -s ${TRAVIS_BUILD_DIR} firebase-arduino && ln -s ${TRAVIS_BUILD_DIR}/src/third-party/arduino-json-5.6.7 ArduinoJson && ln -s ${HOME}/SoftwareSerial ./ && ln -s ${HOME}/Adafruit_NeoPixel ./ && ln -s ${HOME}/Adafruit-GFX-Library ./ && ln -s ${HOME}/Adafruit_SSD1306 ./)
 script:
 - ${ARDUINO_ROOT}/arduino-builder -verbose  -hardware ${ARDUINO_ROOT}/hardware/ -tools ${ARDUINO_ESP8266_ROOT}/tools/ -tools ${ARDUINO_ROOT}/tools-builder/ -fqbn esp8266com:esp8266:nodemcuv2 -libraries ${ARDUINO_HOME}/libraries/ -prefs build.flash_ld=${ARDUINO_ESP8266_ROOT}/tools/sdk/ld/eagle.flash.4m.ld -prefs build.flash_freq=40 -prefs build.flash_size=4M examples/FirebaseDemo_ESP8266/FirebaseDemo_ESP8266.ino
 - ${ARDUINO_ROOT}/arduino-builder -verbose  -hardware ${ARDUINO_ROOT}/hardware/ -tools ${ARDUINO_ESP8266_ROOT}/tools/ -tools ${ARDUINO_ROOT}/tools-builder/ -fqbn esp8266com:esp8266:nodemcuv2 -libraries ${ARDUINO_HOME}/libraries/ -prefs build.flash_ld=${ARDUINO_ESP8266_ROOT}/tools/sdk/ld/eagle.flash.4m.ld -prefs build.flash_freq=40 -prefs build.flash_size=4M examples/FirebaseSerialHost_ESP8266/FirebaseSerialHost_ESP8266.ino

src/Firebase.h

@@ -24,10 +24,8 @@
 #include <memory>
 #include "FirebaseHttpClient.h"
 #include "FirebaseError.h"
-// TODO(edcoyne): move this into our mock_arduino fork where we actually do the
-// override.   
-#define ARDUINO_STRING_OVERRIDE
-#include "third-party/arduino-json-5.3/include/ArduinoJson.h"
+#define ARDUINOJSON_USE_ARDUINO_STRING 1
+#include "third-party/arduino-json-5.6.7/include/ArduinoJson.h"
 
 class FirebaseGet;
 class FirebaseSet;

src/FirebaseCloudMessaging.h

@@ -26,7 +26,8 @@
 #include <vector>
 #include "FirebaseHttpClient.h"
 #include "FirebaseError.h"
-#include "third-party/arduino-json-5.3/include/ArduinoJson.h"
+#define ARDUINOJSON_USE_ARDUINO_STRING 1
+#include "third-party/arduino-json-5.6.7/include/ArduinoJson.h"
 
 // Defines the actual message to the client, for more detail on
 // options and settings see:

src/FirebaseObject.h

@@ -17,7 +17,8 @@
 #ifndef FIREBASE_OBJECT_H
 #define FIREBASE_OBJECT_H
 
-#include "third-party/arduino-json-5.3/include/ArduinoJson.h"
+#define ARDUINOJSON_USE_ARDUINO_STRING 1
+#include "third-party/arduino-json-5.6.7/include/ArduinoJson.h"
 
 #ifndef FIREBASE_JSONBUFFER_SIZE
 #define FIREBASE_JSONBUFFER_SIZE JSON_OBJECT_SIZE(32)