Allow showing additional package metadata alongside name

[mattip]

How difficult would it be to add a --license command line switch and then pipdeptree would output not only the package name and version but also the contents of the LICENSE metadata field?

[naiquevin]

This entirely depends on whether or not pip (used as a library) exposes this information. But it's a good suggestion to include LICENSE info. I'd definitely like to explore this when I get time.