Added pilot app for scoring protein-ligand interactions.
Separately for each ligand in the pose, calculates the weighted two-body
interaction energy between all residues and the given ligand.
The output consists of a sorted list of ligand-residue pairs and their weighted
two-body interaction energies (total, as well as per score-term), with the
residues that contribute most to ligand-binding listed first.
No test changes expected.