Added missing .h to all examples

Author: ed7coyne

examples/FirebasePush_ESP8266/FirebasePush_ESP8266.ino

@@ -17,6 +17,8 @@
 // FirebasePush_ESP8266 is a sample that push a new timestamp to firebase
 // on each reset.
 
+#include <ESP8266WiFi.h>
+
 #include <Firebase.h>
 
 // create firebase client.

examples/FirebaseStream_ESP8266/FirebaseStream_ESP8266.ino

@@ -18,6 +18,7 @@
 // public Firebase and optionally display them on a OLED i2c screen.
 
 #include <Firebase.h>
+#include <ESP8266WiFi.h>
 #include <Adafruit_GFX.h>
 #include <Adafruit_SSD1306.h>
 #include <ArduinoJson.h>

examples/Firebase_ESP8266_LEDs/Firebase_ESP8266_Neopixel/Firebase_ESP8266_Neopixel.ino

@@ -18,6 +18,7 @@
 // to set pixel data using a firebase stream.
 #include <Firebase.h>
 #include <ArduinoJson.h>
+#include <ESP8266WiFi.h>
 
 #include <Adafruit_NeoPixel.h>
 #include "colors_ext.h"