Performance update + WMR support

Arrr Pirates,

We've just released a big performance update. SPT should now run much smoother than ever before. Kudos to Microsoft, Intel, Unity and Valve for pushing this further than we thought.

In addition to this, we've added gun selection mapping for WMR devices to the thumbstick. Haptics are unfortunately not available yet, but that's something MS needs to fix for SteamVR on their end.

Cheers! QC