Better LaTeX support

[xeniagda]

Currently, the LaTeX engine works quite hackishly, by using a combination of pdflatex, (not pdfcrop, as wrongly stated in src/latex/render.rs and pdftoppm.

This has not been tested on any other system than my own MacBook, and has very cryptic errors when something goes wrong, which will likely happen.

[amarmaduke]

You're probably already aware of this, but for my (and anyone else's benefit) this appears to be how manim does it: https://github.com/3b1b/manim/blob/master/manimlib/utils/tex_file_writing.py

i.e. They build a dvi and then use dvisvgm to produce an svg file. I haven't had to chance to dig into how ytesrev renders (aside from it using SDL2) but it might useful to consider switching to an SVG specific renderer like lyon. That would give us easy access to shapes / lines / etc, although I'm not sure how that would change the animation effects.

As an aside, I have access to Windows / Mac / Linux, i've tried the example deck on Windows and Mac. It "kinda works" on windows, though there are some rendering problems (e.g like with the Skull characters)