Merge Step-and-Compare chapter

Hi Greg. This PR is to merge in your step-and-compare chapter. I didn't give it its own chapter as that would impact too many other parts of the doc. (This whole thing needs a massive re-write after RTL anyway). The remainder of the changes are either cosmetic (I like lines shorter than 80 characters) or renaming the ISS to be RM (Simon prefers that term be used). I also removed the term golden reference - by now everyone knows how I feel about that one. 😉

Signed-off-by: Mike Thompson mike@openhwgroup.org