Updates to Brotli compression format, decoder and encoder
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:
* Format change: don't push distances representing static dictionary words to the distance cache.
* Fix decoder invalid memory access bug caused by building a non-complete Huffman tree.
* Add a mode parameter to the encoder interface.
* Use different hashers for text and font mode.
* Add a heuristics to the hasher for skipping non-compressible data.
* Exhaustive search of static dictionary during backward reference search.
14 files changed
