Network Drivers - Milestone #1

Having done some work on the Tulip cards, here are some general
comments.

- we should have both an rx and tx queue and pop/push from the queue
  in the system rx/tx_thread.  this should provide good performance
- order of calling is
	: detect
	: init
- the driver is normally in 2 pieces, one for the general calls and
  one for the device specific stuff.