Introduce acceptance tests with Wallaby

[stevegrossi]

Resolves #36 — Thanks for the suggestion @SherSpock!

And introduce a polyfill for modern JS functionality since Wallaby uses PhantomJS which uses an older version of Webkit which does not support some modern JS React depends on.

To Do

• [x] Figure Out Why Tests Fail Intermittently because the player's name is "Player 1" instead of what was entered into the Prompt ("Yojimbo"):

That text does initially start out as "Player 1" but should be quickly re-rendered with the name "Yojimbo", so it seems like the test isn't waiting long enough for that to happen, or it's happening too slowly 🤔

[stevegrossi]

I'll go ahead and merge this one even though the specs aren't fully fleshed out, since it adds value and has been a long time coming.