Native Blurhash encoder!

This release includes:

• An all new Image encoder! Asynchronously encode Images to Blurhashes straight out of your React Native app:

  const blurhash = await Blurhash.encode('https://blurha.sh/assets/images/img2.jpg', 4, 3);

• Performance improvements for decoding
• Cache improvements to not spawn new threads when not needed
• Improved logging (and warning when props are misused)
• Bugfixes
• Refactoring