Merge branch 'mem-optimize' into develop

modules/bindings/pymod/msms.py

modules/conop/pymod/export_conop.cc

modules/conop/src/conop.cc

modules/conop/src/conop.hh

modules/conop/src/heuristic_builder.cc

modules/conop/src/rule_based_builder.cc

modules/gfx/src/impl/backbone_trace.cc

modules/gfx/src/surface.cc

modules/io/src/mol/entity_io_crd_handler.cc

modules/io/src/mol/entity_io_mae_handler.cc

modules/io/src/mol/pdb_reader.cc

modules/io/src/mol/pdb_writer.cc

modules/io/src/mol/sdf_reader.cc

modules/io/tests/test_io_pdb.cc

modules/io/tests/test_io_sdf.cc

modules/mol/alg/src/entity_to_density.cc

modules/mol/alg/tests/test_superposition.cc

modules/mol/base/pymod/export_atom.cc

modules/mol/base/src/CMakeLists.txt

modules/mol/base/src/atom_base.cc