* Enable hardware serial ports on LPC1768
* Fix compilation errors with other HALs
* FIx order of includes in LPC1768 HAL main.cpp
* Add support for RX_BUFFER_SIZE and TX_BUFFER_SIZE options in Configuration_adv.h
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.