Tue Feb 5 22:48:56 CET 2013

Delay lines

These are just another feedback relation.  No big deal.  Maybe make it
part of fold?

There are mainly 2 way to organize delay memory: per shared or
separate.  The only thing that's important is memory locality, which
is not going to be very predictable.  Maybe best to organize delay
lines in cache line chunks, i.e. multi-channel.