Diff of PDF/1.7

• The added line is THIS COLOR.
• The deleted line is THIS COLOR.
• Go to PDF/1.7.

- https://www.iso.org/standard/51502.html
- http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf

--  http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
- PDF Reference 1.7が出ています
--  http://blog.antenna.co.jp/PDFTool/archives/2006/11/pdf_reference_1.html


- PDFのISO規格化で得たものと失ったもの：担当者が振り返るPDF1.7標準化の道のり
--  http://www.itmedia.co.jp/im/articles/0810/28/news130.html