Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

(i.e. LSB transmitted first on the wire), even though SPI commands and
addresses always have to be big-endian.

device.

Separated the mechanisms of non-volatile storage access and non-volatile
stored options.

that don't provide the full flexibility of a bit-bashing interface.

Temporarily hacked rtl8139.c to use the new interface.