bibtex references

[d70-t]

This PR enables reasonably formatted citations and adds a references section.

[tmieslinger]

Thanks for adding the references! That will be of great help especially in the Science section :)
Currently, the References is the last page of the book and it's the only one with a slight change in the page layout (see attachement) where the footer is moved to the right. Do you know why that happens?

Other than that I am super happy about the setup. I also checked it with two or more authors and it works as expected :)

[d70-t]

Apparently, the tool which generates the references adds an additional closing </div> to the generated HTML output, which completely screws up the remaining part of the page. I'll have to dig a little deeper to find where this comes from exactly.