Allow for filtering coding guidelines by chapter

[Keboo]

Objective: We want to allow for showing only coding guidelines that come from a particular chapter.

We believe the following needs to be done

• In the XML to Markdown converter wrap each guideline in a span with chapter number (extracted from key attribute in XML) with the chapter number as a css class.
• Inject a block of JavaScript and markup to allow for toggling the visibility of items with that class.