Obsolete legacy binary filters

This module contains (substantially) a cut/paste job of the entire
code-base from an ancient time. This was done to facilitate internal
re-factoring, by allowing the old code structure (as codified in the
legacy binary file formats) to remain the same.

The basic idea is that this code runs and spits out big chunks of XML
which are then imported by the more modern code-base, thus providing
legacy filter support to LibreOffice.