[phenixbb] reference model restraints now support multiple reference model files

Hi PHENIX users, After numerous user requests, we've added support to phenix.refine for multiple reference model input files. If you are refining a complex and have reference models for individual components, you may now input as many files as necessary. A parameter file would include: refinement { reference_model { file = "reference_A.pdb" file = "reference_B.pdb" } } Chain matching is still carried out automatically, so simply specifying the file paths is usually enough for the restraints to be generated for refinement. Details of chain matches are printed in the .log file, as well as in the reference_model scope in the .eff file. If anyone has questions, please let me know. Thanks! Jeff