Populate modelCIF atomic fields

[keiran-rowell-unsw]

System distinctions

• .Entity
  • used to store _seq()s
• .AsymUnit
  • _chain() and maybe othe rthings
  • .Assembly use to store _groups of .AsymUnits for ensembles
• .alignment
  • for homology modelling stuff

Atom types

Co-ordinates: .model.Model(.Assembly) to be accessed
Atom type from get_atoms()