Added steps for crossreferencing basho's webmachine diagram

https://raw.github.com/wiki/basho/webmachine/images/http-headers-status-v3.png

I was confused about a few choices of the function names, until I started crossreferencing the source code with the basho diagram. I then completely understood the naming conventions in the implementation, but I found it immensely helpful to have all of the steps cross referenced in the source code.

I hope this is useful.