Update encoder * move `common/port.h` to `includes/port.h` * replace magic more magic numbers with constants * artificially limit window size to 2^18 for quality 0 and 1 * use fixed shifts for quality 0 and 1 hashes * removed `BrotliEncoderWriteMetadata` * added `BROTLI_OPERATION_EMIT_METADATA` instead * deprecated low-level API * fixed MSVC warnings