Implement Fetch API

[macdonst]

Implement the Fetch API where not supported. Look to replace the file transfer plugin if possible. May require implementing XHR.upload.

[macdonst]

Possibly use this plugin: https://www.npmjs.com/package/cordova-plugin-fetch

[dpogue]

Not sure why you'd need a plugin instead of just a polyfill on top of XHR: https://www.npmjs.com/package/whatwg-fetch