Added audio preloading

The new "method" doesn't seem to be loading the audio until it is fired by "start-music" (sorry, I did not pick up on this earlier because I was on localhost :hatched_chick:)
I've repositioned the code in commit 55d4704bb0a6fed82a906e1c023f160d1107018e to allow the audio to be preloaded.
It seems to be working as expected based on Chrome DevTools - Network.