babeljs.io/docs/en/v7-migration
This tries to be as backwards compatible with what we generated with babel 6 as possible.
Babel 7 deprecated stages in favour of explicitly defining what features/syntaxes you're using.
Fixes#2177
* adds babel support for async/await with transpilation to ES2015 generators for backward compatibility with node 6 + working example of function converted to async/await syntax in linter.js
* rewrites run, scan, scanFile, getAddonMetadata and extractMetadata functions
* refactors the rest of the promises in linter.js
* fixes comments from second of review
* reverts unnecessary chahges from third round of review