LICENSE - apply gpl v3 license

Include COPYRIGHT to Nightscout contributors with instructions to
check the git log.

If anyone patches bugs, we should eventually be informed of the issue,
and potential ways to fix it.  A pull request to fix issues would be
delightful.  Same for features.

Our rules are simple:
* stay safe
* #payitforward
Merge branch 'wip/cookie' of github.com:nightscout/android-uploader into wip/cookie