Write tutorial for building a Streams protocol

[JakeSCahill]

Is your feature request related to a problem? Please describe.

We are lacking a tutorials for how to build a simple Streams protocol

Describe the solution you'd like

A very simple tutorial that explains how to build a Streams protocol.

The tutorial should cover:

• Defining a simple application that has one simple message type
• Describing the roles that users will have
• Choosing what cryptography your message type will use
• Writing methods to create, publish, and process your message type