Update dependencies
Pandoc-scripting: ignore header attributes XXX

This is a compile fix for some compile errors, not sure it's the right one.
Format is now a newtype: adapt to this, part 1

This is search-n-replace.
Format is now a newtype: adapt to this, part 2

Done by hand, but easy.
Remove duplicate exception handler

Maybe there's some smart reason for it, but I don't see it.
Fix exception-related compile errors
Fix compile errors from biblio API

The API has been rewritten, so here's a mixture of updates and
commenting out. I have commented out everything bibliography-related
which hadn't an easy fix (one code fragment).

I've also removed pieces which seem to have no correspondent in the new
API, namely stateCitations and writerBiblioFiles: from the types, it
looks like we don't need to provide this, because readBiblioFile,
readCSLFile and processCites appear to do all the work (which makes
sense). No idea whether that's actually the case, though.

Getting the code to work will require actual testing (this isn't the
code where typechecking means much), so let's get this thing compiling
first.

This needs to add a dependency on containers; I've picked no version
range (see comments).