- Set string representation of compound to show compound ID
  (fix #102)
- Set PPI string representation to PPI ID - PPI name
  (fix #103)
- Set string representation of CompoundAction to "Compound ID"
  on "PPI" (fix #104)
- PDB ID in CompoundAction is actually PDB ligand ID
  (fix #105)


Former-commit-id: f91d63f3a9091f6da14673c0eb9015ffcfc5b087