In order to make the license that applies to each file as clear as possible, and to be consistent with elasticsearch, we are adding Apache 2.0 license headers to the top of each file.
Existence of this header is enforced by eslint and tslint and missing headers were automatically added in the last commit by running:
```
node scripts/eslint --fix && node scripts/tslint --fix
```
* [grunt/build] refactor _build:notice task to not depend on npm
The _build:notice task used to rely on the output of `npm ls` to determine where modules were defined, but the task now just asks `license-checker` to include the `realPath` of the modules it describes in it's output, which is ultimately the same thing but works with `yarn` too.
* [grunt/licenses] convert to use lib/packages/getInstalledPackages()
* [grunt/notice/generate] test generateNoticeText()
* [grunt/licenses] tested assertLicensesValid()
* [npm] remove npm dev dep
* [tasks/lib/packages] do not include kibana in "installed packages"
* [tasks/lib/notice] join all notices with the same separator
- Now you'll see a path of the parent dependencies when a dependency fails to licenses task, so you can identify the offending root dependency.
- ES2015ify the licenses task.
