v0.4.1

Added FastMSC, FasterMSC, PAMMEDSIL and PAMSIL clustering,
to optimize the (Medoid) Silhouette directly.

For details on these methods, please see the upcoming publication
Lars Lenssen, Erich Schubert:
Clustering by Direct Optimization of the Medoid Silhouette
In: 15th International Conference on Similarity Search and Applications (SISAP 2022)
https://doi.org/10.1007/978-3-031-17849-8_15