Add example showing asciidoctor -> docbook -> pdf

[elygre]

Add a new example that generates pdf through the use of docbook and the jdocbook gradle plugin.

[mojavelinux]

I support having this example in the repository. Generating PDF via DocBook is still a very important workflow until Asciidoctor PDF reaches a certain level of maturity.

I haven't had a chance yet to review the sample project. If someone could give it a try, that would help move things along.

[rwinch]

Thanks for the sample @elygre!

I agree something like this would be very valuable to include. There are a few problems at the moment:

• This project is not included in the main settings.gradle
• This project is not built entirely / included in the main deploy task. This is related to the fact that we are invoking "gradlew asciidoctor" for every subproject and then including the output from asciidoctor subtask. This new project has a task of a different name that needs invoked, so we need to better align it. You can what gets deployed at http://rwinch.github.io/asciidoctor-gradle-examples/

At the moment I don't have much time to sort this out, but I thought I would respond so you knew why it isn't being merged just yet.