resolves asciidoctor/asciidoctor-documentation#18 corrects copycss info

- corrects copycss documentation in user manual, render, and theme docs
- corrects linkcss documentation in user manual, render, and theme docs
- corrects link reference between documentation
- adds code and image examples for rendering and stylesheets
- adds include files for each section of rendering a document
- introduces the magical, mystical wolpertinger
Merge pull request #144 from graphitefriction/stylesheet-include-file

resolves asciidoctor/asciidoctor-documentation#18 corrects copycss info