the two slide pdfs from the previous commits

See merge request ahf/onion-tex!4

accidentally omitted in the previous branches because of the .gitignore
lines.

the idea is to have the pdfs here, as presented, so future people don't
need to install tikz or whatever to see what the slides look like, and
also so people can know what the slides actually looked like even when
onion-tex has changed in the future.

s28 'area one' presentation from 2021

See merge request ahf/onion-tex!3

slides for arma's defcon22 talk

See merge request ahf/onion-tex!2

Correctly include the onioncolors package in onion color theme

See merge request ahf/onion-tex!1

The onion color theme requires the onion colors to be defined. Without
this include, this command:

     pandoc -t beamer -V colortheme:onion [...]

.. crashes with:

   ! Package xcolor Error: Undefined color `OnionBlack'.

By specifying the dependency, we can use *only* the color theme without
importing the rest of the more... elaborate theme which has many more
side effects than just changing colors.

Add dgoulet's talk at McGill University 2019

Signed-off-by: David Goulet <dgoulet@ev0ke.net>