Add page formats

http://www.printi.com.br/sites/default/files/data/guida_pdf/Guia-de-impressao.pdf

http://www.cl.cam.ac.uk/~mgk25/iso-paper.html

https://github.com/MrRio/jsPDF/blob/master/dist/jspdf.source.js#L370-L410

https://github.com/ariya/phantomjs/blob/master/examples/rasterize.js

https://github.com/ariya/phantomjs/blob/master/examples/printmargins.js
