Specify License in package.json

[sverrejoh]

The README file specifies the MIT Licence, but the field is missing from package.json.

[tunnckoCore]

@rauchg and because recently npm updated its guidelines on license metadata in package.json files
ms is listed in www.npm1k.org

[Lykathia]

This pull request looks to duplicate #42 and issue #32.

Having the license declared in the file would help compatibility with tools such as webjars.

[Lykathia]

@rauchg now that #42 has been merged, can it be published and this + #32 closed?

[sverrejoh]

Thanks for fixing it by accepting #42. Sorry I didn't search properly before creating this pull request.

I'll close it now.