Update U8glib URL

Marlin/Marlin.ino

     #include <LCD.h>
     #include <LiquidCrystal_I2C.h>
   #elif ENABLED(DOGLCD)
-    #include <U8glib.h> // library for graphics LCD by Oli Kraus (https://code.google.com/p/u8glib/)
+    #include <U8glib.h> // library for graphics LCD by Oli Kraus (https://github.com/olikraus/U8glib_Arduino)
   #else
     #include <LiquidCrystal.h> // library for character LCD
   #endif

Marlin/dogm_lcd_implementation.h

  *
  * With the use of:
  * u8glib by Oliver Kraus
- * http://code.google.com/p/u8glib/
+ * https://github.com/olikraus/U8glib_Arduino
  * License: http://opensource.org/licenses/BSD-3-Clause
  */