Closes#5345
Runs tectonic on STDIN instead of a temporary .tex file, so that it
looks in the working directory for `\include` and `\input` like the rest
of the engines.
Allows overriding the output directory without messing up the args
with `--pdf-engine-opt=--outdir --pdf-engine-opt="$DIR"`.
Previously this looked in the filesystem, even if pandoc
was compiled with `embed_data_files` (and sometimes it looked
in a nonexistent build directory). Now the bash completion
script just includes a hard-coded list of data file names.
See #4549.
* Rename --latex-engine to --pdf-engine
* In `Text.Pandoc.Options.WriterOptions`, rename `writerLaTeXEngine` to `writerPdfEngine` and `writerLaTeXArgs` to `writerPdfArgs`.
* Add support for `weasyprint` and `prince`, in addition to `wkhtmltopdf`, for PDF generation via HTML (closes#3906).
* `Text.Pandoc.PDF.html2pdf`: use stdin instead of intermediate HTML file
