Meeko

- RDKit replaces OpenBabel
- tertiary amides are rotatable if the nitrogen substituents are different
- fix OpenBabel inconsistency in which some anilines were kept rigid (https://github.com/forlilab/Meeko/issues/7)
- fix incorrect typing of nitrogens with +1 formal charge (https://github.com/ccsb-scripps/AutoDock-Vina/issues/64)
- add Boron atom type
- aromatic sulfur now type S instead of SA (not H-bond acceptor anymore)
- drop pH option from MoleculePreparation

- Bug fixes
- Add PDBQTMolecule and other post-docking analysis code
- SMARTS based atom typing
- RDKit dependency
- SMILES string in PDBQT files to create RDKit molecules from docking results