Update tutorial

Disko,

Here is my first take at updating the tutorial docs. They should now match your code in master. 

I will update the Installation docs to make them consistent with the updated tutorial, and send you a separate pull request. (I will remove your |version| variable for now.) When we get close to the 1.0.0 release, we can decide how to move forward with regard to docs and code versioning.

I did not yet spend much time cleaning up language. I focused on making sure they were correct.