Add preprocessor magic to the error definitions to enable every error
usage to be tracked.

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resources has been revoked by the registrant of the domain.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

Add commands `iwstat' (to list 802.11-specific status information for
802.11 devices) and `iwlist' (to scan for available networks and print
a list along with security information).

Signed-off-by: Marty Connor <mdc@etherboot.org>