chemfp 5.1 is out, my package for #cheminformatics fingerprints

Most of the new features are related to "superimposed" binary coding of count fingerprints. These do a good job of approximating the count Tanimoto when using the binary Tanimoto.

- integrated "superimposed" into RDKit binary fp generation

- added:
- EState count&superimposed fps (RDKit and OEChem)
- Gobbi 2D pharmacophore count fps (RDKit)
- LINGO count&superimposed fps from SMILES strings

More at https://chemfp.com/docs/whats_new_in_51.html .