Bug fix release.
Add basic biblioref support. Its specific attributes
are not handled yet.
Allow the appendices to be followed by other sections.
Add the ability to convert on the fly SVG figures to PDF through inskscape: apply patch #2821475 from David Necas.
Improve the ability to format in bold or italic the elements embedded in
programlistings or screens.
Add the parameters:
index.tocdepth.
index.numbered.
bibliography.tocdepth.
bibliography.numbered.
xref.hypermarkup.
A number of bug fixes.