Package createrepo_c for PyPI

[dkliban]

Pulp depends on createrepo_c to generate RPM repository metadata. Having a package available on PyPI would enable Pulp to manage RPM repositories on non-PRM based Linux distributions.
This work was started here: #96
However, the author ran into some problems that may already be resolved. https://groups.google.com/forum/#!topic/scikit-build/XYfZFT2iFJM

[Conan-Kudo]

There's no way to put the Python bindings into PyPI right now while there's no way to plug CMake into a python wheel building process.

[dralley]

@Conan-Kudo Not true, scikit-build can do that.

http://scikit-build.readthedocs.io/en/latest/

My PR is mostly working (#96) but I'm still figuring out a few issues. Producing bdists works fine but sdists are broken. I have working packages for both (sdist and bdist) but I'm still trying to get one configuration to work for both, without breaking the current cmake build+install process.

[dralley]

@dkliban @Conan-Kudo

New PR #103. Everything that I've tested so far works. I'll be a bit more thorough with testing it tomorrow, and a third party from the scikit-build team is going to double check one of the commits as well.

You may prefer to split some of the changes out into other PRs, which would be no problem for me.

[goosemania]

This is resolved by Pulp team and can be closed.
PR #103 is merged, bindings are published on PyPI.