Firing the weapon now makes a sound. I've implemented this by spawning
the playback component on the bullet rather than the gun. This seemed
easier than figuring out how to reset a playback component that lives on
the ship entity -- although thats probably better for memory access
patterns.
It's a simple one-shot sound clip that gets dispatched as one more part
of the ship impact routine.
The GameAssets struct has been updated to have an array of handles for
audio assets (just the one, for now).
This sound file, and the next several, are all from Kenney
(www.kenney.nl).
