External logic from the 68060 to the NeXT 68040 socket.

I believe that I have the external logic required for the 68060 to the 68040 socket on the NeXT slab. I've picked the level shifter part, which is the 74ALVC164245 from ST. The TI sn74lvc16t245 will work as well.

Another thing that I determined is that the DLE line latch on the 68040 was wired to be transparent, so no worries there.