Relicense files for which I am the sole author (as identified by
util/relicense.pl).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

The implementation of inet_aton() has an unknown provenance.  Rewrite
this code to avoid potential licensing uncertainty.

Also move the code from core/misc.c to its logical home in net/ipv4.c,
and add a few extra test cases.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Signed-off-by: Michael Brown <mcb30@ipxe.org>