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resources has been revoked by the registrant of the domain.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>

Merge the pxe_set_netdev()+pxe_[un]hook_int1a() pattern into a single
pxe_[de]activate() call.

pxe_init_structures() fills in the fields of the !PXE and PXENV+
structures that aren't known until gPXE starts up.  Once gPXE is
started, these values will never change.

Make pxe_init_structures() an initialisation function so that PXE
users don't have to worry about calling it.

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

Both the script and PXE images types will claim a zero-length image.
Inhibit this to avoid end-user surprises.

Remove the assortment of miscellaneous hacks to guess the "network
boot device", and replace them each with a call to last_opened_netdev().

It still isn't guaranteed correct, but it won't be any worse than
before, and it will at least be consistent.

When trying to find the "first open network device", it helps to
actually check the NETDEV_OPEN flag.

PXE is a catch-all image format with no signature checks.  If an
unsupported image file is loaded, it will be treated as a PXE image.  In
most cases, the image will be too large to be loaded as a PXE image (which
has to fit in base memory), so the error returned to the user will be that
the segment could not fit within the memory region.

Add an explicit check to pxe_image.c to reject images larger than base
memory with ENOEXEC.

Add ENOEXEC to the error string table.

list.

Added FEATURE() macros to most relevant (non-driver) files.

Use generic fields in struct device_description rather than assuming
that the struct device * is contained within a pci_device or
isapnp_device; this assumption is broken when using the undionly
driver.

Add PXENV_UNDI_SET_STATION_ADDRESS.

Implement PXENV_RESTART_TFTP.

Move pxe_boot() code to pxe_image.c

Add IMAGE_PXE to use the new image format framework.  "kernel pxelinux.0"
now works.

PXE code now compiles without errors (though it won't actually work).