Pass only purely numeric points to kmeans module

This fixes the case where None values could potentially be passed to kmeans methods. kmeans is known to only work on purely numeric data so any non-numeric points are filtered out for kmeans interactions then added back in to the list before returning results.

Signed-off-by: Don Naegely <naegelyd@gmail.com>
Merge pull request #246 from cbmi/no-nulls-kmeans

Pass only purely numeric points to kmeans module