Graph reference 3.0:

- enable easily-configurable language-dependent
  meta descriptions of graph objects.
- split `graph_objs_meta.json` output file
  into language folders (`./graph_objs/<lang>/`)
- split setup, meta-generating functions,
  meta shortcuts and run command into separate files (in `./scripts/`)
- replicate previous `graph_objs_mets.json` (yeah!) 
G->NAN, in general, that way you can format with `**G`, not `G['NAN']`