resolves #137 turns section numbers on in user manual

- changes toc2 to toc
- adds toclevels=2
- cleans up a few links
- moves several sections to enriching doc part
- cleans up section titles and nesting levels

This pull request closes issue #137 though it doesn't satisfy the requirement of turning on Table/Image/and Figure captions.
During the course of this branch, several feature needs were discovered that, once included in Asciidoctor, will allow the part, section and block numbering to improve.
A new issue should be created to update the user manual captions for when those enhancements are implemented.