fix issues with travis build

Author: kotl

contrib/test/FirebaseArduino_test.cpp

@@ -16,7 +16,7 @@
 
 #include "FirebaseObject.h"
 #include "gtest/gtest.h"
-#include "WString.h"
+
 
 TEST(FirebaseObjectTest, GetBool) {
   FirebaseObject obj("true");

src/FirebaseObject.h

@@ -17,14 +17,18 @@
 #ifndef FIREBASE_OBJECT_H
 #define FIREBASE_OBJECT_H
 
-#include <ArduinoJson.h>
+
+#include "WString.h"
 #include <memory>
 
+#include <ArduinoJson.h>
+
+
 #ifndef FIREBASE_JSONBUFFER_SIZE
 #define FIREBASE_JSONBUFFER_SIZE JSON_OBJECT_SIZE(32)
 #endif // FIREBASE_JSONBUFFER_SIZE
 
-using std::shared_ptr;
+
 
 /**
  * Represents value stored in firebase, may be a singular value (leaf node) or