Expermintal features

[sr229]

To be able to test features without compromising our release schedule, I'm introducing a risk-free way to test experimental commands.

How it works:

• Any command that is tagged experimental on its object won't be able to be loaded by CommandHandler until it satisfies either of these two conditions:
  - command has no experimental property in its Object.
  - NODE_ENV is development.

• The modules command has to handle Object.experimental and read if it exists or false. Otherwise, the command object won't load in a production environment. The only way it would be accessible is setting NODE_ENV to development.

• the modules command would warn the user if it tries to load a experimental command (for NODE_ENV instances set to development only. For production environments, they will not load.).