Reverses the page order of PDFs using flask, pyPDF, and google app engine.

Sources:

• File upload styling: http://labs.abeautifulsite.net/demos/bootstrap-file-inputs/
• Flask file uploads: http://flask.pocoo.org/docs/patterns/fileuploads/
• Reversing order of pdfs: http://stackoverflow.com/questions/5425439/how-do-i-reverse-the-order-of-the-pages-in-a-pdf-file-using-pypdf
• Using stringIO and send_file: http://flask.pocoo.org/snippets/32/