Every frame sends a bunch of audio samples in a channel. This channel is
consumed by the audio Read() function which is called asynchronously. There's
all kinds of timing issues where the audio/video are not aligned.
Issues:
- There's a large delay between the audio being produced and it being played
- Something with the timing is wrong. The first not of lemonade stand and the
system beep are both incorrect. Changing the CPU frequency fixes it for one
but not for the other. This means something must be wrong in the cycle
counting.
Also added FPS display that can be toggled with ctrl-alt-F.
Basic memory management has been implemented since $c100-$cfff needs flipping
with soft switches during Apple //e boot. All memory reads & writes now go
through the MMU. Memory is also dynamically allocated and associated with the
CPU state.
