Redesigned the Readme doc

[jeremybeal11]

I noticed the lessons hopped around which threw me off a bit, so i restructured the page so it it can flow with the lesson a bit better, and i have moved the exercises to the bottom so they can understand it better after reading all of the lessons.

[jeremybeal11]

@differentialderek can you give feedback on this?

[dhsorens]

I like this organization. It makes sense to me to join the two pizza examples together and keep more theoretical things up at the front. That said, as it is I really like how the examples fit into the flow of the document—feels good to do as you learn. I also like how the original starts with "We learned last time ... " but I'm not really sure where to put the "Receiving before sending" section.

If I'm honest I don't have any strong feelings about the organization. Both make sense to me.

[jeremybeal11]

ok thanks @differentialderek, i wanted to get some form of feedback before i resumed issuing my PR. although if not one is complaining then my edits may not be needed.

[JoshOrndorff]

feels good to do as you learn

That's what I was going for.