Audit

This remove papers w/ explicit permissions/copyright against distribution and adds *some* of them as URLs within each of the categories. Some *papers* were not actually papers; so, those were removed.

@papers-we-love/owners / @papers-we-love/collaborators please review and check if you feel any are awry. This done me less papers in the repo, but a cleaner corpus of good stuff and URLs all go straight to the PDFs anyway.

#### TODO

We need to update the main README and/or wiki w/ updates to filtering out permissions and how the URL tier works. If anyone wants to take that on after reviewing, let me know.