Add an option to generate man pages

[tukusejssirs]

Related #128

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I’d like to generate man pages for the CLI. This is a Linuxy thing to have a man page for each program/app.

Also, as it was already said in #128, we can define the path to man page files in package.json (see the docs).

I have also create an issue in commander issue tracker (see tj/commander.js#1875), as currently, there no way to get an object with all the data needed to generate the man pages. We could parse the output of helpInformation() (for each commands presumably) which returns the formatted string as it would be output to the terminal.