Graph reference 3.0:

- enable easily-configurable language-dependent
  meta description 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 seperate files
- replicate previous `graph_objs_mets.json` (yeah!)
- test for Python/Matlab dependencies
This sets up the config file to be used for the table of contents on e.g. https://plot.ly/python/reference/