Several files define the ARRAY_SIZE() macro as used in Linux.  Provide
a common definition for this in include/compiler.h.

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

Detected by sparse.

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

Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain.  Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.

Also update README, LOG and COPYRIGHTS to remove obsolete information.

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