PS4 gamepad needs mappings

[ericlathrop]

Got a bug report:

So I installed my blutetooth PS 4 Gamepad on Windows10 and tried your test page. I noticed that there are differences between Firefox 48.0.1 and Chrome 52.0.2743.116 with keys assignments. I used the Button “Square” which changed in Browser Chrome Button X to true an in Browser Firefox Button a to true.

The PS4 gamepad needs to be mapped, including on Win10

[ericlathrop]

Just mapped a bunch fo ps4 stuff, but PS4/win/ff is broke.