Upgrade to React v16 (for tests)

[fahad19]

This PR upgrades all dependencies to be compatible with React v16.

While latest release of FrintJS on npm is already compatible with React 16, the tests in the repo are still written targeting v15.

Before merge

• Fix failing tests in frint-router-react (Fixed frint-router-react tests for React 16 compatibility #343)

After merge

• Update React version in examples

What's done

• All relevant dependencies upgraded
• Tests: requestAnimationFrame is set globally for React v16
• Tests: Enzyme adapter for React v16 is set via frint-test-utils/register hook

What's failing

Tests from frint-router-react are failing. You can reproduce them by running:

$ git checkout react16

$ npm install
$ npm run bootstrap

$ (cd ./packages/frint-router-react && npm test)

[fahad19]

Fix is in progress in #343.

[coveralls]

Coverage decreased (-0.03%) to 97.439% when pulling a76b217 on react16 into 8a00fdd on master.

[coveralls]

Coverage decreased (-0.03%) to 97.439% when pulling a76b217 on react16 into 8a00fdd on master.