Fixes install on python2, and adding old-style arXiv references.
### Fixed bugs
### Fixed bugs
- Fixes install on python2, and adding old-style arXiv references.
- Fixes adding papers with slashes in their citekeys. [(#179)](https://github.com/pubs/pubs/pull/179) (thanks [Amlesh Sivanantham](https://github.com/zamlz) for reporting.)
- Fixes adding papers with slashes in their citekeys. [(#179)](https://github.com/pubs/pubs/pull/179) (thanks [Amlesh Sivanantham](https://github.com/zamlz) for reporting.)
- Fix missing readme.md for python2 pip install. [(#174)](https://github.com/pubs/pubs/pull/174)
- Fix missing readme.md for python2 pip install. [(#174)](https://github.com/pubs/pubs/pull/174)