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.
I'm in favor of capitalizing Merkle in Merkle tree, since it derives from a proper name, but I think we should be consistent and capitalize it in all cases.  (Except, of course, when referring to case-sensitive variables, functions, and other code.)