WIP: Add minted (pygmentize) as option for including code (provides better syntax highlighting).

Maybe consider using minted for code display instead of listings as it - in my opinion - provides a slightly better syntax highlighting for the included code. And as e.g. this ShareLaTeX page shows, it provides a lot of customization options as well as supported languages.

As an example I added the Euclid's GCD as a minted version to the PDF. Admittedly the environment handling is not solved ideally as of now, as sometimes the code will break over different pages or - even more problematic - sometimes even the caption is shifted to a new page when the included codes fills the prior one.