Host the metadata file somewhere

[anacronw]

It'd be cool if there had a listing of popular node libraries that I manually update their licenses by hand. The --meta flag could be passed the location of such a file and it would help resolve some licenses.

For example, mocha is very particular about what files are packaged with "files" property in their package.json. Thus, the README and LICENSE are stripped out during the install and npm-license can't guess at what it is.