the _version.py file is autogenerated at build time from git tag using setuptools_scm; the pyclipper.__version__ variable exports that, as it's common in python packaging. This allows clients to import pyclipper and check its __version__ without needing to query the package metadata (which may be missing when pyclipper is embedded in native applications).
it's not very useful (using the sdist from PyPI is ok, no need to support
zip archives from github), and causes issues with latest setuptools_scm
Fixes#19
After publishing 1.0.6 via twine command, I noticed the PKG-INFO 'Description' was empty...
That's because setup.py was missing 'long_description' field.
So I had to manually upload a modified PKG-INFO with the content of the current README.rst.
For next releases this won't be necessary.
The 'License' was also missing in the sdist PKG-INFO, so I added that too.
setuptools_scm is a setuptools plugin that uses git metadata to manage python package versions
https://github.com/pypa/setuptools_scm
It also replaces the use of MANIFEST.in, by including in the soruce distribution all the
files that are under version control (using `git ls-files`).
An extra plugin 'setuptools_scm_git_archive' also adds support for git archives,
e.g the .zip files automatically generated on Github.
https://github.com/Changaco/setuptools_scm_git_archive
For example, one could do: `pip install https://github.com/greginvm/pyclipper/archive/1.0.4.zip`
Note that installing from git archives currently works only for tagged commits, because
of limitations of git archive format itself.
However, for non-tagged commits one can still install from the git repo:
`pip install git+https://github.com/greginvm/pyclipper`
Having e.g. Cython installed in a virtualenv inside the project root make pytest also find the Cython test cases. These take a lot of time and also fail without some additional libraries being installed.
