Enable automated testing of apps that use paper

Enable Automated Testing for apps that use [paper.js

paper.js tries to touch the canvas just by requiring it, so the default test runner in create-react-app cannot test it :

Test suite failed to run
Canvas [object HTMLCanvasElement] is unable to provide a 2D context.
> 1 | let paper = require("paper");

So I changed it to jest-electron.

from pRegroup-done-2020

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