Hi!

I have two comments about scipy.spatial distance functions.

First, scipy/spatial/src/distance.c contains several interesting
distance measures. However, the vector versions are not visible outside
the file because they are not declared in distance.h (for instance,
euclidean_distance). Only the pdist_* and cdist_* versions are made
visible. I would like to use the "raw" distance measures directly for
some other functions, so would it be ok to introduce those in distance.h?

Second, squared Euclidean distance is computed by taking the square of
the Euclidean distance. I think it would make more sense to do it the
other way around: the Euclidean distance is computed by taking the
square root of the squared Euclidean distance.

If these suggestions are ok, I can try to implement them or how should I
proceed? Or any other comments?