Add neon acceleration for rgb and rgb to yuv conversions #111

Job	Run time
Lint (Format, Clippy)	30s
Sanitizer	4m 2s
Build (ubuntu-latest, Rust stable)	2m 36s
Build (WASM)	10s
Build (ubuntu-latest, Rust beta)	2m 32s
Build (ubuntu-latest, Rust nightly)	2m 31s
Build (windows-latest, Rust stable)	4m 26s
Build (windows-latest, Rust beta)	3m 31s
Build (windows-latest, Rust nightly)	3m 31s
Build (macos-latest, Rust stable)	48s
Build (macos-latest, Rust beta)	1m 0s
Build (macos-latest, Rust nightly)	55s
Coverage	1m 48s
	28m 20s

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