Change internal representation of pedigrees to follow the proposal @ https://phenotips.org/Design/REST_Family2:
This issue implements the following version of Pedigree JSON:
}"id"/code field defined there
implementation note: if at any point layout disagrees with pedigree, layout is scrapped and pedigree is re-laid-out
only "members" field is mandatory, however since pedigree should be a connected component if there is more than one member there must be a corresponding link in the "relationships".