Review Sound Support, including Repeats and dsound_wait()

[mesheets]

Repeat behavior in the code does not appear to match the documentation, as the code appears to support repeat count tracking.

Also need to verify the functionality of dsound_wait().

Possibly add tunes from the following repository to the demos?

• https://github.com/jbernalr/brickossongs

[mesheets]

dsound_play(), dsound_wait(), and dsound_stop() have all been used in the music.c demo program.