Add sources for PDF test files

[fladi]

Thanks for providing this great module! I would like to package it for the Debian archive and there is a minor issue when running the tests during package build: Debian packages should have the source of all its files in their modifiable format. For PDF this is usually something like a TeX file or similar. Would you be able to provide those formats along with the PDFs for the tests in your repo? Otherwise I'll have to exclude the tests from the Debian package which is not the best solution I guess.

[jalan]

The current PDFs came from all different sources. It may take some time to come up with tex equivalents for each one, but I will look into it.

I see two potential difficulties:

• the corrupt.pdf and corrupt_page.pdf files were sort of handmade, since they each need to be corrupt in a certain way to satisfy the tests
• both_passwords.pdf and user_password.pdf are password-locked, and I'm not sure if tex can do that. Might require another tool for that step

Thanks!