Merge branch 'develop' into ldt

modules/io/src/mol/pdb_reader.cc

modules/io/src/mol/pdb_writer.cc

modules/io/tests/test_io_pdb.cc

modules/io/tests/testfiles/pdb/bzdng-318.pdb

modules/mol/base/src/atom_base.cc

modules/mol/base/src/atom_base.hh

modules/mol/base/src/editor_base.cc

modules/mol/base/src/editor_base.hh

modules/mol/base/src/impl/atom_group.hh

modules/mol/base/src/impl/residue_impl.cc

modules/mol/base/src/impl/residue_impl.hh