Please remove .c files from git repo

[socketpair]

1. These files are auto-generated and therefore should not be placed in git
2. These files are bound to specific range of Python versions, may contain bugs generated by Cython of unknown (your) version
3. Absolutely useless files without python devel infrastructure, compiler.

Everyone, who wants to build the package from scratch, must ensure that Cython works.

I would suggest adding these files to .gitignore