Dedicated pub/sub compression support
Pub/sub now supports the use of dedicated compressors, not only the shared one. We've supported dedicated compressors for regular WebSocket::send calls a long time, but now WebSocket::publish will provide the same compression ratios.
A "dedicated" compressor is one with a sliding window, per-socket. This compressor provides better compression for small, mostly-repeated messages in exchange for per-socket memory usage.
A recommended dedicated compressor is the DEDICATED_COMPRESOR_3KB as it uses only 3KB per socket.