vke & link level addressing

[Chris Turner]

Looking at implementing this so my vkernels can be configured
via dhcp without trusting the vkernel's dhcp client
to give the correct hostname option..

Should be pretty straightforward, but 2 questions (at least) come to mind:

1) What should the syntax be?

   Thinking just allowing an ethernet address in place of the IP
   address, e.g. auto:bridge0:001122334455 or perhaps
   auto:bridge0:0x001122334455 .. Existing use of ':' prevents
   'standard' ':' notation ..

   This also prevents assigning an ethernet address and a IP address
   at the same time.

   unless something like:

   auto:bridge0:10.10.10.1.001122334455 is permitted, and the parsing
   counts the dots between the ':' characters before passing along

   Suggestions welcome..

2) The `link_addr` manual page notes that this function has been
   depreciated in favor of addr2ascii, yet ifconfig itself uses
   link_addr instead of addr2ascii. Which form is 'correct' and should
   be used?

Thanks,

- Chris