replace isomorphic fetch with whatwg-fetch and node-fetch

[hampsterx]

isomorphic-fetch doesn't work properly with webpack

matthew-andrews/isomorphic-fetch#31 (comment)

[coveralls]

Coverage decreased (-1.2%) to 92.353% when pulling d951b0a on replace_isomorphic_fetch into 4da4cb3 on master.

[coveralls]

Coverage decreased (-1.2%) to 92.353% when pulling d951b0a on replace_isomorphic_fetch into 4da4cb3 on master.

[paulmelnikow]

You may be interested in taking a look at https://github.com/qubyte/fetch-ponyfill, which is an isomorphic fetch which unlike isomorphic-fetch does not replace the native fetch. It works correctly in Node and the browser, and is compatible with Webpack, and Browserify. It might streamline things for you a bit, since you can just require fetch-ponyfill, and it takes care of whatwg-fetch and node-fetch under the hood.