Interactivity environment variable instead for examples/tutorials instead of code variable

[filipinascimento]

Most of the examples and tutorials have a variable to enable or disable interactivity. Interactivity should be disabled for docs building and testing. However, most of the users will clone the repo and try to run the examples without knowing about the interactivity variable, resulting in nothing being displayed.

My suggestion is to have an environment variable that if defined, will run these demos/tutorials/examples without interactivity. This could be defined inside the docs building process.

I think this would easy the access of new users to fury as the demos will just run in their machines, without any extra changes.