out-of-tree driver code.

to generate the initial transmission; this cuts off around 0.3s per
instantiated connection.

No Microsoft intellectual property was harmed in the production of
this code.

executing any image, not just a script.  (This will enable pxelinux to
use relative URIs, should it wish to.)

wasn't meant for my local "master" branch ;)
This reverts commit 373022108b.

otherwise.  :(

Some shuffling around of the image management code; this needs tidying up.

list.

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

and generate DHCP options to indicate features to DHCP server (and to
PXE NBPs).

options are in main makefile now

Print error status using strerror().

initiator.  This table needs to be replaced by something similar to
iBFT (i.e. scanned for and identified by signature, rather than being
at a fixed address), but it works for now.