Misc fixes

- changed HEADER_SIZE constant from 8 to 7 to reflect message structure
- removed duplicate utility folder in UIPEthernet that prevented proper
compilation
- removed unnecessary includes in EthernetGateway that prevented proper
compilation

libraries/UIPEthernet/utility/clock-arch.c

@@ -1,28 +0,0 @@
-/*
- clock-arch.c - Arduino implementation of uIP clock device.
- Copyright (c) 2010 Adam Nielsen <malvineous@shikadi.net>
- All rights reserved.
-
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-#include <Arduino.h>
-#include "clock-arch.h"
-
-clock_time_t
-clock_time(void)
-{
-  return (clock_time_t) millis();
-}