add HardwareSerial and SoftwareSerial for Re-ARM.

HardwareSerial has been tested on Uart0 (debug header) and Uart3 (i2c connector)
Software Serial has been tested to work bi-directionally at 9600 and 115200
using pins 6 and 63 on J5, and unidirectionally (write only) at 250000.
The code used to test was Teemuatlut's tmc2208 patch, and a few small changes to main used to echo recieved chars back to a host pc.

Marlin/frameworks/CMSIS/LPC1768/lib/Print.cpp

@@ -28,7 +28,10 @@
 #include "Print.h"
 #include <stdarg.h>
 
-#define PrintfEnable  0
+#define PrintfEnable  1
+typedef signed short sint16_t;
+typedef signed long sint32_t;
+
 // Public Methods //////////////////////////////////////////////////////////////
 
 /* default implementation: may be overridden */