predict and score functions

[pchronz]

For some use cases predict and score functions would be helpful.
The predict function should return the assigned clusters for a set of observations like this for kmeans:

function predict(kmresult, X)
    dmat = Distances.pairwise(Distances.SqEuclidean(), kmresult.centers, X)   
    mod(findmin(dmat, 1)[2] .- 1, size(dmat, 1)) .+ 1
end

The score function should assign given observations and return the 1/totalcost for these observations and could look like this for kmeans:

function score(kmresult, X)
    dmat = Distances.pairwise(Distances.SqEuclidean(), kmresult.centers, X)   
    sum(findmin(dmat, 1)[1])
end

Of course, it would be great to have those functions for all of the available clustering algorithms.