- atusb.c (main), board.h (board_init), board.c (board_init): moved
clock and I/O initialization to board file
- board.h (led), board.c (led), atusb.c (main): abstracted LED setting
in function "led" instead of open-coding it
- spi.c (spi_init): set nSS to 1 before enabling the output, so that we
don't generate what looks like an empty SPI transaction
- io.h: renamed to board.h
- Makefile (OBJS): added board.o
- atusb.c (reset_rf): moved to board.c
- board.h (reset_rf): give reset_rf a proper declaration
- atusb.c, ep.c, spi.c: include board.h instead of io.h
- Makefile (OBJS): added spi.o
- spi.h, spi.c, atusb.c: moved SPI functions to new file
- spi.h (spi), spi.c (spi), atusb.c (main): renamed function "spi" to
"spi_io"
- atusb.c (reset_rf, main): moved transceiver reset to separate function
