Merge tag 'v0.4.0'

libwebp 0.4.0
- 12/19/13: version 0.4.0
  * improved gif2webp tool
  * numerous fixes, compression improvement and speed-up
  * dither option added to decoder (dwebp -dither 50 ...)
  * improved multi-threaded modes (-mt option)
  * improved filtering strength determination
  * New function: WebPMuxGetCanvasSize
  * BMP and TIFF format output added to 'dwebp'
  * Significant memory reduction for decoding lossy images with alpha.
  * Intertwined decoding of RGB and alpha for a shorter
    time-to-first-decoded-pixel.
  * WebPIterator has a new member 'has_alpha' denoting whether the frame
    contains transparency.
  * Container spec amended with new 'blending method' for animation.

* tag 'v0.4.0':
  update ChangeLog
  update NEWS description with new general features
  gif2webp: don't use C99 %zu
  cwebp: fix metadata output w/lossy+alpha
  makefile.unix: clean up libgif2webp_util.a
  update Changelog
  bump version to 0.4.0
  update AUTHORS & .mailmap
  update NEWS for 0.4.0

Change-Id: I6df1b512fe0b697192f1f9b29431cd59aa6063d1

examples/cwebp.c

@@ -497,6 +497,7 @@ static int WriteWebPWithMetadata(FILE* const out,
     if (has_vp8x) {  // update the existing VP8X flags
       webp[kChunkHeaderSize] |= (uint8_t)(flags & 0xff);
       ok = ok && (fwrite(webp, kVP8XChunkSize, 1, out) == 1);
+      webp += kVP8XChunkSize;
       webp_size -= kVP8XChunkSize;
     } else {
       const int is_lossless = !memcmp(webp, "VP8L", kTagSize);