Added box-grouped, added functionality to run.py (see below)

You now have these options:

- run all code
  python run.py code

- run all images
  python run.py images

- run single code
  python run.py code examplename

- run single image
  python run.py images examplename

- run multiple code
  python run.py code examplename examplename ...

- run multiple images
  python run.py images examplename examplename ...
Merge branch 'DocumentationFriday_May23' of https://github.com/plotly/graph-decoder into DocumentationFriday_May23

Conflicts:
	json-examples/chart-types/box-plots.json
Modified run.py to ignore non .json files.