DevDocs corrections part 1

Started reviewing the developer docs, finding lots of things to correct. I'll do more later, but please review this batch first so I know what, if anything, needs to be fixed moving forward - I'm not entirely sure on the markdownish format used.
This is a minor issue, but I feel the block chain is an inert thing which is operated on by peers, so it would be incorrect to say the block chain expects something but correct to say that peers or the p2p network expect that thing.