Lorenzo

I have added a test here but there is something wrong, please take a look: https://github.com/AlanRace/smartcore/pull/1

thanks @AlanRace it is probably better to adhere to the DenseMatrix format, so it would be nice for the method to return the transposed values or directly a DenseMatrix.

yeah, probably in the shape returned by `from_vector` and `from_array` is handier. thanks again

@morenol @VolodymyrOrlov could you please take a look to the WASM test failing? it looks like we have different results for different targets. Looks like rounding works different for WASM,...

@alexis2804 unfortunately we have problems with some tests, you can take a look at them by fetching this branch

I will proceed implementing FastPair or MST-Linkage depending how difficult it is to implement the latest, or hopefully both. For the latest, I will use `std::collections::LinkedList`.

@VolodymyrOrlov Please help about how to implement `cmp` for `PairwiseDissimilarity`. `cmp` is implemented for `RealNumber`?

FastPair implemented. Moving to integrating this first algorithm into `agglomerative`, adding the post-processing steps. Cleanup at the end.

Please provide feedback on interface

> Ideally, end user interface should be as simple as possible. It would be great to have a simple meta-class that represents agglomerative clustering algorithm, similar to AgglomerativeClustering. Particular implementation...