Audio recording feature

[coffeevalenbat]

The ability to record tracks to audio files (WAV, MP3, etc) would be very nice, something similar to GBSPlay's record feature.

[baines]

I've pushed some new code to allow writing .wav files.

There are two new command line arguments:

• -w <filename.wav> to enable "wav write" mode, and give the filename to write to.
• -t <seconds> to say how much audio you want to write to the file, default 120s.

If you're comfortable building it from source, let me know if this works for you.