update NEWS
drop iOS framework update, that was included in 0.5.2
* webpmux gained a -duration option allowing for frame timing modification
* new img2webp utility allowing a sequence of images to be converted to
animated webp
- * WebPDecoder framework for IOS, WebP framework now contains the encoder
* API changes:
- libwebp:
WebPPictureSharpARGBToYUVA
