the logic for making sure to chdir() into the build directory has been
sequestered into doctypes/common.py (and output.py); additionally, it is
smarter to put the resource copying logic, there, as well
important to validate the document before processing it;
Note! Adding this feature flushed out a number of sketchy corners of a few of
our documents, but almost everything validated already.
rely directly on the logging module directly instead of through tldp.utils
add the BaseDoctype to all of the modules (even though not all are
implemented)
the config_fragment function becomes a part of each doctype class, allowing
better encapsulation of most/all document type handling logic
the config_fragment function becomes a staticmethod called argparse
add argparse-style support to each doctype module, for path-configurables
also add the runtime discovery of files needed for document handling (e.g. XSL
and DSSSL files)