Feature Request: NSF Sound Recorder Track Splitting

[torridgristle]

Lately I've been recording sound effects in NSF files with Mesen since it's the best option of course but I've had to slice up the single WAV of all the sound effects on my own.

When Mesen has an NSF loaded, or any music / sound format in case there's other formats, it should start recording to a new file with the track number in the filename when the skip / next track button is pressed. This way the user decides when to end the playback instead of needing some complicated guesswork performed by Mesen and also it's neatly split by track automatically, it just seems perfect to me.

The only additional thing I could think of regarding splitting by track is detecting a complete lack of sound output (not sound instructions but the actual output since there's a DC offset trailing behind notes often) and then halting writing to file but continue saving to a buffer for situations where if it's the natural end of a sound then the file is ended right at silence but if something else comes after it then the silence is uninterrupted. This should be optional I reckon since it could theoretically have a large recording of silence in a buffer. I'm not even sure if this is a good solution to just wanting WAVs to not have extra silence at the end.