Produce a pdf rahter than an info page

Targets #351.

The initial setup may still lack a view bits (e.g. inclusion of LaTeX packages).
What's really required here is the `FindLATEX` module, which is provided by the cmake installation. That module itself sets a few variables (e.g. `PDFLATEX_COMPILER`).
Requiring this package does _not_ mean we require `pdflatex` or anything latex related _at all_.