Looping Music test part 2

Changes:
--added better-cut clips to the bgm & sfx assets, deleted the old ones
--disabled 3D Sound on the clips so now bgm is non-diegetic and plays
back in stereo (also set BGMPlayer's Z-position to 0 just in case)
--tweaked the script and got rid of the 2-second delay between game
startup and music start
--added comments to the script so hopefully others can figure it out
--got rid of "Test Scene 1 clone.scene" because it's an old version of
marrowGroveMusicTestscene
--renamed the scene to marrowGrove instead of morrowGrove, whoops