SECURITY: decoder: fix integer overflow when input chunk is larger than 2GiB (CVE-2020-8927)
Other changes:
- add support WASM (emscripten) build
- brotli -v now reports raw / compressed size
- build files / docs maintenance
- reduce sources tarball size
- decoder: minor speed / memory usage improvements
- encoder: fix rare access to uninitialized data in ring-buffer
- encoder: improve support for platforms that does not have log2
- encoder: better support for MSVC (replacement for __builtin_clz and __builtin_ctzll
- python: decompress now reports error if there is unused after the end of compressed input