QUICify

## What's New in beta.3

### Added
- Velocity proxy support (Velocity proxy port)
- Unreliable datagram lane for QUIC
- Player latency now reflects real path RTT

### Fixed
- Major stability fixes for stream multiplexing (dropped/reordered packets, drain/close edge cases, secondary stream crashes)
- Certificate loading no longer accepts mismatched key/cert pairs, and cleanup errors no longer hide real failures
- Fixed a crash related to the debug screen entries
- Fixed profile registration check on the client
- Various other bugfixes and internal cleanup