Bounce sound plays when hitting the bar or a brick.

Classes and code to handle sound effects have been added, however,
no sound file can be provided due to possible copyright reasons.
There's also a bug caused when a sound file is played several times
in a short timespan (maybe less than a second) where Qt will print
a message on the screen about 'Aborting aboutToFinish handling'.
This does not cause problems on Linux, however, it must be tested
on other operating systems.