Only parse interesting files in a project

[zsol]

We don't care about random .py files in the source dist:

• sphinx config files
• test files
• benchmarks

Check out https://py.wtf/numpy for a good example of what we shouldn't index.

There are some options and tools we could use:

• https://github.com/python-packaging/dowsing
• fetch pure python bdist_wheels if available
• blocklist stuff 😞

[zsol]

#116 helped for projects that have a pure python bdist_wheel (like pathspec), but there are other opportunities to improve:

• frozenlist (github) doesn't have a pure python bdist_wheel. We could use dowsing to filter out random .py files for these. For frozenlist specifically, this needs to be implemented first: Support setuptools custom discovery python-packaging/dowsing#69
• numpy is hopeless. Here's where packages are being declared - we'd have to run setup.py to discover these. The only sane way for us is to blocklist paths specifically.