WIP commit.  Still in the process of refactoring this code.
Added a target param to constructor to differentiate between generating HTML vs. MAN pages.
Creating more high-level methods in style.
Merge remote-tracking branch 'upstream/develop' into develop
WIP commit. Merging doc pipeline into domain model branch.
Reworking to allow a document object to be passed along to all event handlers.
More refactoring (and hopefully simplification) of the events.
Simplifying the document event generation down to a single, generic function.  Simplifying event handlers and fixing some output errors in style.py.
Further simplification of doc event handlers.  The initialize method in the base class now handles all standard registration.  Subclasses just need to implement methods named after the event they want to handle (e.g. doc-title -> def doc_title(self, ...)).