Dependencies:
    xpdf (for pdftotext)
    python
    git


Generating diffs of pdf documents:
    Inspiration: http://the-gay-bar.com/2009/03/24/versioning-pdf-files-with-git/
    Add the following to your ~/.gitconfig or .git/config in your repository
    """
[diff "pdf"]
    textconv="pdf() { pdftotext $1 -; }; pdf"
    """
    Now add the following line to the .gitattributes file in your
    repository:
    """
*.pdf diff=pdf
    """