Add complete example

[MartinThoma]

I want to have a single PDF which is small in file size and covers many cases. Specifically:

• Alphabets: English text, Arabic text, cyrillic, chinese, mathematical formulas
• Formatting: 3-column, tables, multi-level lists, header, footer (e.g. page number), title page
• Images: Floating, in-line, overlay / watermark,
• Links: Linked index page, linked footnotes
• Annotations: Comments, replies to comments
• A form with text input (single-line and multi-line), select, option, submit button

This could allow pypdf to have a better test coverage with just a single file.