Adding form element to output

Poppler takes care of almost everything, I simply added the form tags at the end of every page.
Yes, I think without ID the input fields are less useful, but the prefixes `text-` and `cb-` may not be clear enough.
I'd suggest using `CSS_INPUT_TEXT_CN` or `CSS_INPUT_RADIO_CN`

And please register the values (e.g. height, width) using `StateManager`, as done in other files.