[test] Include failing code within failed test result output

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[main] Defer "initialising devices" message until initialising devices

Allow the "initialising devices" message to show up on consoles which
require initialisation, by deferring it until after initialise() has
completed.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[console] Pass escape sequence context to ANSI escape sequence handlers

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[pixbuf] Add generic concept of a pixel buffer

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[image] Allow for non-executable image formats

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[image] Add image_pixbuf() to create pixel buffer from image

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[pnm] Add support for PNM images

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