uStreamer 5.42: Reduced stream latency!

While I was working on HDMI passthrough for V4 Plus (I didn't forget what we promised!), I found a way to reduce the stream latency.

Now 1080p stream with H.264 can reach ~110ms on LAN. That is, -50ms compared to the previous result.

BTW all PiKVMs, including V3 and DIY builds, will receive this update.