Convert all files to Unix line-ends with dos2unix

Switch to Unix line ends (DOS ones are annoying in Git), and remove
trailing spaces from pandoc-lit.cabal.
Update dependencies XXX
Pandoc-scripting: ignore header attributes XXX

This is an incomplete compile fix, 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
Avoid warnings from biblio API XXX

The API has been rewritten, so here's a mixture of updates and
commenting out. 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.