[build] Rename gPXE to iPXE

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resources has been revoked by the registrant of the domain.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

README

@@ -1,53 +1,8 @@
-gPXE README File
+iPXE README File
 
-gPXE is an implementation of the PXE specification for network
-booting, with extensions to allow additional features such as booting
-via HTTP, iSCSI, and AoE.  
-
-In generally, gPXE is compatible with the industry-standard PXE
-specification, and also supports Etherboot .nbi file loading and some
-additional protocols and features.
-
-For more detailed information about gPXE, please visit our project
-website at: http://etherboot.org/
-
-BUILDING gPXE IMAGE FROM SOURCE
-
-If you don't want to install development tools, and have access to the
-Web, you can get gPXE and Etherboot ROM images made on demand from
-http://rom-o-matic.net/
-
-If you would like to compile gPXE images from source, here are some tips.
-
-We normally compile gPXE images on x86, 32-bit Linux machines. It is
-possible to also use x86-64 machines. We use gcc compiler options to
-create 32-bit output.
-
-It is important to have the necessary software  packages installed.  A gcc-based
-toolchain is required.
-
-The following packages (at least) are required:
-
-  - a gcc tool chain (gcc 3.x or gcc 4.x)
-  - binutils
-  - perl
-  - syslinux
-  - mtools
-  
-To test your environment, cd to the "src" directory and type:
+Quick start guide:
 
+   cd src
    make
 
-You should see a lot of output, and when it stops, the "bin" directory
-should be populated with gPXE images and object files.
-
-To learn more about what to build and how to use gPXE, please visit our
-project website at http://etherboot.org/ , particularly the "howto" section.
-
-CONTACTING US
-
-Pointers to our project mailing lists are on http://etherboot.org/
-
-Real-time help is often available on IRC on the #etherboot channel of
-irc.freenode.net.
-
+For any more detailed instructions, see http://ipxe.org