Merge this implementation back into the original repository

[rphes]

Now that the Cython implementation has proven itself to work on at least a few use-cases, it is worth merging its code back into https://github.com/nicodv/kmodes. The author, @nicodv, has previously expressed his interest in seeing what's possible.

At the moment I can't spend significant time on this issue, but help is welcome. Some of the things that should happen are:

• Rename the package back to kmodes (not sure why I changed that in the first place)
• Implement K-Modes as well, or drop it completely, as K-Prototypes is capable of doing exactly the same (I prefer the latter)
  • If K-Modes is dropped the package should maybe be renamed to kprototypes or some variant of that
• Add some decent tests for the native parts of the code
• Document the new API (e.g. tuple, pandas support)
• Implement the todos contained in the code (e.g. missing functionality)

The previous discussion for reference: nicodv#57