[usb] New Spec (V 0.6) is here !

[Rudolf Usselmann <rudi@asics.ws>]

Some of the changes are:

Added Change bars
Changed buffer memory back to single port SSRAM
Removed quadruple buffering (back to double buffering)
Enhanced the way buffers work, added description
Added data organization section
Added various references to latency and bandwidth requirements
Added USB core behavior section

I hope this is the final version with buffer/latency changes !
Next I hope to fill in USB protocol/operation sections !

The spec can be downloaded from:
http://www.opencores.org/cores/usb/usb_doc.pdf

Cheers !
rudi