v0.2.1

Make output match Nintendo's DSP-ADPCM v2.3 encoder's non-SIMD implementation.

The SIMD implementation varies ever-so-slightly from the non-SIMD implementation. We're talking thousandths of a percent difference when doing a byte-by-byte comparison.
Later versions of Nintendo's encoder change the output a bit, so this C# version will stick with v2.3.