Log Message:
Changes 0.4.1:
* AArch64 (arm64) & MIPS support/optimizations
* NEON assembly additions:
  - ~25% faster lossy decode / encode (-m 4)
  - ~10% faster lossless decode
  - ~5-10% faster lossless encode (-m 3/4)
* dwebp/vwebp can read from stdin
* cwebp/gif2webp can write to stdout
* cwebp can read webp files; useful if storing sources as webp lossless