Use asciidoctor for user guide

[moaxcp]

The user guide should be written in asciidoctor. Figure out how asciidoctor will work for this project and implement it. At the end of this task there should be some basic guidance for graph-dsl.

Basic Documentation to Add

1. Using graph-dsl with with grape
2. Add vertices and edges
3. show actual code and results from running actual code

Problems to solve

1. ensure the version of graph-dsl in scripts is updated from gradle
2. include code from documentation scripts
3. include results from running documentation scripts

Documentation policy

Some policies should be made on how to introduce new features in the guide. How to tag code for use in asciidoctor. When to display results from example code.

When something is first used include all the code. After it is introduced including all the code is not needed. For example, show the usage of the static graph {...} method once and then after that section of the documentation the developer should assume code is run from within a dsl entry point.