+ Improve PNP compatible ROM header. Test more.

+ Some cards (e.g. 3c509) need a hard reset after being used by OS;
maybe should do a reset when etherboot starts.

+ Code improvement in many places to reduce size. Structure assignment
instead of many field assignment statements.

+ Clean up xstart code in start32.S.

+ Is back to back PIO a good idea? Maybe should use versions with delay?

+ Restructuring of code not complete; currently the WD, 3C503 and
NE drivers duplicate a lot of code due to multiple compilation with
different conditionals. Could move common code into common routines.
Not a high priority as there is no duplication for a single NIC
binary, as would be the case for production use.

+ Include Gero's extensions to the VendorTags (resolver library).
