[libre-riscv-dev] buffered pipeline

[Luke Kenneth Casson Leighton]

yep added a setup function to the Stage class API which is only called
(from the Pipeline elaborate) if it exists, passing in the m instance
as well as the input variable.

i added an example in the unit test which does a compare, i'm not sure
what's going on there as it works regardless of whether the src1 and
src2 are set to signed or to unsigned.

l.