Convert .wav to .flac

[kmturley]

Problem
.wav files are high-quality lossless audio files and the preferred choice for music production. They come at a cost. of filesize:

Solution
.flac uses lossless compression. FLAC files are smaller than corresponding PCM-encoded WAV files, since PCM doesn't allow for lossless compression and just represents the data as-is.

The main SFZ players support flac as it is part of the ARIA spec:
https://sfzformat.com/opcodes/sample.html#formats

Examples of other SFZ instruments using the .flac format:
https://github.com/sfzinstruments/virtuosity_drums/tree/master/Samples/room/kick
https://github.com/sfzinstruments/WilkinsonAudio.NakedDrums/tree/master/Wilkinson%20Audio/Naked%20Drums/Samples
https://github.com/sfzinstruments/SalamanderGrandPiano/tree/master/Samples

I converted all .wav to .flac using the following commands:

brew install ffmpeg
for file in $(find . -type f -name '*.wav'); do ffmpeg -i "$file" "${file%.*}.flac"; done
find . -type f -name '*.sfz' -exec sed -i '' s/wav/flac/g {} +
find . -type f -name '*.txt' -exec sed -i '' s/wav/flac/g {} +
find . -type f -name '*.wav' -type f -delete

This PR is the result.