Semi missing license

[stefnotch]

The package.json specifies the ISC License, however the Readme.md only includes a part of the relevant legal text.
https://en.wikipedia.org/wiki/ISC_license#License_terms

Especially the following part is missing

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

[Edison Neza]

At the moment updated just the GitHub readme. For npm will be updated in the next version.

Thanks!