Reaction Toolkit Introduction:

New object properties:

• Atoms have a "map class" property.

  dt_mapclass(atom) => dt_Integer value
  dt_setmapclass(atom, value) => dt_Boolean success

• Molecules have a "role" in a reaction, which is one of: DX_REACTANT, DX_AGENT, DX_PRODUCT.

  dt_getrole(reaction, molecule) => dt_Integer constant
  dt_addcomponent(reaction, molecule, role) => dt_Handle mol_copy

• Molecules can have a reaction as their parent.