Fix project licensing issues

* Use valid [License SPDX Code](https://spdx.org/licenses/) for package.json
* Set the missing `url` name to point to our LICENSE
* Include short text for GPL-3.0+ instead of full with properly copyright and attribute to the project
* In the short text rewrite url to point to full GPL-3.0+ text [found on GNU](http://www.gnu.org/licenses/gpl.txt) ... they aren't going away anytime soon.
Change license to not use blob but use raw

Applies to #177
Merge pull request #177 from Martii/fixPackageJSONLicense

Fix project licensing issues