Update qsys to include audio cores
Add an AudioController Class

This class is responsible for enabling and disabling the output of
sound.  It stores a buffer of the sound wave to play.  It has the
ability to play mutliple sounds, but for now this has been disabled to
save space.
Add a Sound class

This struct holds the current index of the specific sound and handles
the loading from the SD card.  The AudioController can hold multiple
Sound structs in order to allow multiple sounds to play at once.
Add an ISR for the audio interrupts

Checks for a write interrupt (when 75% of the audio buffer has been
played) and writes as many values as possible to the left and right
audio channels.