Bump loop module to (c) 2020

loop/data/convert_binaries.py

loop/doc/all_atom.rst

loop/doc/backbone.rst

loop/doc/index.rst

loop/doc/load_loop_objects.rst

loop/doc/mm_system_creation.rst

loop/doc/structure_db.rst

loop/doc/torsion_sampler.rst

loop/pymod/__init__.py

loop/pymod/export_all_atom_env.cc

loop/pymod/export_all_atom_positions.cc

loop/pymod/export_amino_acid_atoms.cc

loop/pymod/export_backbone.cc

loop/pymod/export_forcefield_lookup.cc

loop/pymod/export_frag_db.cc

loop/pymod/export_fragger.cc

loop/pymod/export_loop_object_loader.cc

loop/pymod/export_mm_system_creator.cc

loop/pymod/export_psipred_prediction.cc

loop/pymod/export_structure_db.cc