Deleted spi.py
Adding pin mode stuff to serial example
Also slight tidying of spi_test.h.
Changed pin settings in serial_test.cpp for serial pins.
Also, fixed the header text in all files to correct a typo-
"by me a beer" to "buy me a beer" (DOH).
Fixed serial input part of serial_test.cpp
Wasn't initializing the input buffer variable, so the do-while loop
wasn't working properly.