Added import of Wire Library to make I2C LCD support compilable

Marlin/Marlin.pde

@@ -34,7 +34,12 @@
 #include "pins.h"
 
 #ifdef ULTRA_LCD
-#include <LiquidCrystal.h>
+  #ifdef LCD_I2C
+    #include <Wire.h>
+    #include <LiquidCrystal_I2C.h>
+  #else
+    #include <LiquidCrystal.h>
+  #endif
 #endif
 
 #if DIGIPOTSS_PIN > -1

Marlin/ultralcd_implementation_hitachi_HD44780.h

@@ -11,6 +11,7 @@
   #define LCD_CLASS LiquidCrystalRus
 #else
   #ifdef LCD_I2C
+    #include <Wire.h>
     #include <LiquidCrystal_I2C.h>
     #define LCD_CLASS LiquidCrystal_I2C
   #else