[libre-riscv-dev] buffered pipeline

[Luke Kenneth Casson Leighton]

btw just a heads-up, i'm going to need a multi-in, multi-out
(crossbar'd) variant of the pipeline, which can be specified to take
an array of inputs and an array of outputs.  i started that with
InputGroup except that InputGroup uses john dawson's half-clock-speed
ACK/STB signalling convention.

l.