Maximum distance setting for SteamAudioPlayer

[stechyo]

Unless a sound is quite loud, it's probably pointless to spend CPU time on processing its occlusion/reflection. We can let the user configure this, perhaps with different values for direct effects (occlusion/transmission) and indirect effects (reflections).

This is a matter of binding some get/setters to something in local state, and then using that to skip adding simulation inputs on SteamAudioServer::tick().