Changes:

• [2023-04-29] Molecule: improved fingerprint method to be uniq for different atom kinds or diffent bond kinds.
• [2023-04-29] Molecule: new symbols and atomic_numbers methods
• [2023-04-20] Added functions for visualization of molecules using jmol/agui
• [2023-04-20] Added spdkit-view script for easy viewing of molecular files