improved re-sync handling of SequenceNumberStats

removed "duplicate" category since it's not 100% accurate
added bot_procedural back in
Merge pull request #3249 from ey6es/metavoxels

Cull heightfield/points/spanners against frustum, added simple "erase heightfield" tool.
Merge pull request #3246 from wangyix/inbound_audio_stream

Improved SequenceNumberStats handling of out-of-sync seq nums