Feature/change to babel

[dkildar]

Changed to babel and fixed node build

[feruzm]

@dkildar With this changes, I am getting this error in our https://github.com/ecency/ecency-vision codebase.

using like this: const hs = require('hivesigner'),

Please check or add test for all these:

1. check if require of module works properly.
2. check if .me method working ok in all different imports new hs.Client({accessToken: code}).me().then((r: { name: string }) => r.name) works properly

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