QR codes for latex files

This pull request will allow a latex file to declare 
```
style=qr
```
in the document class to allow printing/recognization of QR codes.

It is important to note that -shell-escape is being used; meaning any latex that is being processed can be exposed to malicious behavior if any user input is being shuttled directly to the latex without scrubbing.

We opted for a simple external python script to generate the QR codes instead of a package like pst-barcode.

Any further input is welcomed.