Update lib/libwebp

5cd43e4 Add -incremental option to dwebp
54b8e3f webpmux: DisplayInfo(): remove unnecessary error checks.
40ae352 fix memleak in WebPIDelete()
d966265 mux.h doc: WebPMuxGetFrame() can return WEBP_MUX_MEMORY_ERROR too.
0e6747f webpmux -info: display dimensions and has_alpha per frame
d78a82c Sanity check for underflow
8498f4b Merge "remove -Wshadow warnings"
e89c6fc Avoid a potential memleak
3ebe175 Merge "break down the proba 4D-array into some handy structs"
6a44550 break down the proba 4D-array into some handy structs
2f5e893 remove -Wshadow warnings
bf3a29b Merge "add proper WEBP_HAVE_GIF and WEBP_HAVE_GL flags"
2b0a759 Merge "fix some warnings from static analysis"
22dd07c mux.h: Some doc corrections
79ff034 add proper WEBP_HAVE_GIF and WEBP_HAVE_GL flags
d51f45f fix some warnings from static analysis
d134307 fix conversion warning on MSVC
d538cea gif2webp: Support a 'min' and 'max'  key frame interval
80b54e1 allow search with token buffer loop and fix PARTITION0 problem
b7d4e04 add VP8EstimateTokenSize()
10fddf5 enc/quant.c: silence a warning
399cd45 Merge "fix compile error on ARM/gcc"
9f24519 encoder: misc rate-related fixes
c663bb2 Merge "simplify VP8IteratorSaveBoundary() arg passing"
fa46b31 Demux.h: Correct a method name reference
f8398c9 fix compile error on ARM/gcc
f691f0e simplify VP8IteratorSaveBoundary() arg passing
42542be up to 6% faster encoding with clang compiler
93402f0 multi-threaded segment analysis
7e2d659 Merge "remove the PACK() bit-packing tricks"
c13fecf remove the PACK() bit-packing tricks
2fd091c Merge "use NULL for lf_stats_ testing, not bool"
b11c9d6 dwebp: use default dct_method
4bb8465 Merge "(de)mux.h: wrap pseudo-code in /* */"
cfb56b1 make -pass option work with token buffers
5416aab (de)mux.h: wrap pseudo-code in /* */
35dba33 use NULL for lf_stats_ testing, not bool
733a7fa enc->Iterator memory cleanup
e81fac8 Add support for "no blend" in webpmux binary
3b80bc4 gif2webp: Separate out each step into a method
bef7e9c Add doc precision about demux object keeping pointers to data.
61405a1 dwebp: enable stdout output with WIC
6eabb88 Merge "Animated WebP: add "do no blend" option to spec"
be20dec fix compilation for BITS 24
e58cc13 Merge "dwebp: s/unsigned char/uint8_t/"
72501d4 dwebp: s/unsigned char/uint8_t/
2c9633e Merge "gif2webp: Insert independent frames at regular intervals."
f0d6a14 gif2webp: Insert independent frames at regular intervals.
b25a6fb yuv.h: fix indent
ede3602 Merge "cosmetics: fix indent"
3a65122 dwebp: fix stdout related output
388a724 cosmetics: fix indent
4c7322c Merge "dsp: msvc compatibility"
d50c7e3 Merge "5-7% faster SSE2 versions of YUV->RGB conversion functions"
b8ab784 Merge "simplify upsampler calls: only allow 'bottom' to be NULL"
df6cebf 5-7% faster SSE2 versions of YUV->RGB conversion functions
ad6ac32 simplify upsampler calls: only allow 'bottom' to be NULL
a5e8afa output to stdout if file name is "-"
f358450 dsp: msvc compatibility
43a7c8e Merge "cosmetics"
4c5f19c Merge "bit_reader.h: cosmetics"
f72fab7 cosmetics
14dd5e7 fix const-ness
b20aec4 Merge "Support for 'do not blend' option in vwebp"
dcf6522 Support for 'do not blend' option in vwebp
d5bad03 Animated WebP: add "do no blend" option to spec
a2f5f73 Merge "Support for "Do not blend" in mux and demux libraries"
e081f2f Pack code & extra_bits to Struct (VP8LPrefixCode).
6284854 Support for "Do not blend" in mux and demux libraries
f486aaa Merge "slightly faster ParseIntraMode"
d171863 slightly faster ParseIntraMode
3ceca8a bit_reader.h: cosmetics
69257f7 Create LUT for PrefixEncode.
988b708 add WebPWorkerExecute() for convenient bypass
06e2498 Merge "VP8EncIterator clean-up"
de4d4ad VP8EncIterator clean-up
7bbe952 Merge "cosmetics: thread.c: drop a redundant comment"
da41148 cosmetics: thread.c: drop a redundant comment
feb4b6e thread.h: #ifdef when checking WEBP_USE_THREAD
8924a3a thread.c: drop WebPWorker prefix from static funcs
1aed8f2 Merge "fix indent"
4038ed1 fix indent
1693fd9 Demux: A new state WEBP_DEMUX_PARSE_ERROR
8dcae8b fix rescaling-with-alpha inaccuracy
11249ab Merge changes I9b4dc36c,I4e0eef4d
52508a1 Mux: support parsing unknown chunks within a frame/fragment.
05db057 WebPMuxSetChunk: remove unused variable
8ba1bf6 Stricter check for presence of alpha when writing lossless images
a03c351 Demux: WebPIterator now also denotes if the frame has alpha.
6df743a Decoder: handle fragments case correctly too.
faa4b07 Support for unknown chunks in mux library
7d60bbc Speed up HashChainFindCopy function.
6674014 Speedup Alpha plane encoding.
Tabs for indentation, miscellaneous cleanup
Stop claiming to support non-HTTP protocols
Pass non-200 status code responses through
Truncate data buffer before telling our client about the response
Change method of remembering that request are internal

Set a property on the internal request to avoid multiple-handling rather
than checking the scheme again.
Convert url through an -absoluteString to avoid dropping components
Compare scheme case-insensitively
Optionally claim all .webp requests

… without requiring a prefixed scheme.
Turn some more warnings on
Use a streaming decoder for the NSURLProtocol implementation
Expose error-vending methods on the streaming decoders
Fail NSURLProtocol loads if decoding fails