Add the dependencies on PyPI `cmake` and `ninja` packages only
if they are not available, in order to facilitate using the system
tools. This avoids unnecessarily installing third-party binaries,
and improves portability by permitting users to use downstream-patched
CMake.
* release python
* fix twine upload only push tags, fix linux bdist_wheel so path error
* fix long_description_content_type
* remove log print
* set cibuildwheel version 1.6.3
* add pyproject.toml
* set release python only on push tag
* add ci build python 2.7
* remove python2.7; update readme.md
Michał Górny