Change the include script to continuously alter graphics path

[bhuvy2]

Is your feature request related to a problem? Please describe.
Right now we pick the graphics path from the root of the project, meaning one has to do this

introc/images/blah

This isn't a good abstraction. Ideally, each chapter shouldn't care about all the other chapters and should have its own copy of images.

Describe the solution you'd like
https://tex.stackexchange.com/questions/49488/changing-the-working-directory-when-including-files-in-a-subdirectory

In order.tex, generate like the following

\graphicspath{{./introc/}}
\include{./introc/introc.tex}
\graphicspath{{./processes/}}
...

And change all the references to be directory local

images/blah

The other issue is that now we'll have to change the pandoc_wiki_filter to make sure to resolve the full path or all other images will be broken.

This will also help with #79 because the chapters won't care about their outlying folders.

Describe alternatives you've considered
We could use luatex, but any solution in plain tex is better.

Additional context
N/A