added minimal compound library

modules/conop/pymod/export_compound.cc

modules/conop/src/CMakeLists.txt

modules/conop/src/compound.hh

modules/conop/src/compound_lib.cc

modules/conop/src/compound_lib.hh

modules/conop/src/compound_lib_base.cc

modules/conop/src/compound_lib_base.hh

modules/conop/src/heuristic.cc

modules/conop/src/heuristic.hh

modules/conop/src/minimal_compound_lib.cc

modules/conop/src/minimal_compound_lib.hh

modules/conop/src/standard_compounds.cc