update readme

FOR DISCUSSION ONLY. DO NOT MERGE.

@zdne @pksunkara @smizell I have edited the README and one example file. I am holding of on other example files pending chatting with @zdne. ITMT, I have added a few comments in-line that need clarification per an email I sent @zdne and questions I have.

Also, I have switched the order of presentation here from JSON first to MSON first in the examples. The point of this document is to introduce MSON and the JSON makes more sense once you read the MSON vs. the opposite (my experience reading this the first time). In the context of MSON being used to replace JSON in api-blueprint, maybe the logic is opposite, but if we are going to share this generally with people, then I think the order I have it is correct.
@zdne Need to modify this to show when needed with useful case. Not sure the point of this example. Does the lack of JSON imply this would just be markdown only vs. MSON? Kind of confusing with parts escaped and others not.