WIP: pure python

[joshmoore]

Following on from #259 (comment), I dropped the blosc module and am slowly making changes in the background to use native blosc wheels, turning this into a pure Python module. If anyone would like to add commits, please feel free (especially if you know what you are doing unlike myself...)

TODO:

• Unit tests and/or doctests in docstrings
• tox -e py39 passes locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• tox -e docs passes locally
• GitHub Actions CI passes
• Test coverage to 100% (Coveralls passes)

[pep8speaks]

Hello @joshmoore! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file numcodecs/lz4.py:

Line 13:34: E203 whitespace before ':'
Line 13:35: E231 missing whitespace after ':'
Line 13:39: E252 missing whitespace around parameter equals
Line 13:40: E252 missing whitespace around parameter equals

Comment last updated at 2021-02-18 15:13:38 UTC

[normanrz]

I wonder if we should close this PR? There is been very little progress in a long time.
Additionally, in my view the main value proposition of numcodecs is the distribution of built wheels for the various codecs. If we drop that, I would argue that zarr-python should depend on the upstream codec libraries (e.g. blosc, cramjam) directly.