Waybackpack

Small change to add more informative error when the API does not respect `showDupeCount=true`: https://github.com/jsvine/waybackpack/commit/9e896adfcdbd0bdcbe3a26f6f623273c81a58848 h/t CaptSolo

Quickfix to handle `--no-clobber` before `--delay` when downloading assets: https://github.com/jsvine/waybackpack/commit/6dc2dcffea52df2602829174e4b549a11baaebfd

- d960fac Have only one source of truth for version
- a982516 Use os.path.join instead of '/'.join
- b22ae0f Update copyright years
- 7cfda8b Replace "." and ".." components in URL-derived paths
- f3d54ed Don't rely on assert for timestamp format validation
- c3c2190 Tighten timestamp format regexp
- febb1c2 Fix outdated claims of Python2 support in docs

Many thanks to jwilk for most of the above.

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*Noting prior changes here:*

- 94fdff8 Add ConnectTimeout handling, bump to 0.6.1

- 242b8f1 Add --delay-retry for pausing between retries
- 2dc24e9 Add --delay option to pause between fetches (71)

- Added support for multiple `--collapse` values (h/t shijialee via 49)
- Added checks for funky/dangerous timestamps (h/t jwilk via 63)
- Improved handling of colon in port numbers (and other tricky characters) (h/t peci1 via 58)
- Added `MANIFEST.in` (h/t pmlandwehr via 25)
- Switched testing from the defunct `nosetests` to `pytest`
- Ran psf/black, isort, and flake8 over codebase
- Added Makefile