SSLproxy 0.9.9

• Fix fd leak, do not setup dst again in autossl, issue #88 reported by @victorjulien
• Fix memory leak in config load, reported by valgrind
• Disable r/w cbs and clear all cbs before all bufferevent_free() calls
  • Also, disable the events first, then clear the callbacks, for conventional pattern
• Check fd usage before content logging, issue #88 reported by @victorjulien
  • This change is expected to prevent sslproxy to crash if it runs out of fds while content logging
• Make sure the other conn end not closed before using it
• Increase sizes of bufs used in ClientHello parsing as a defensive measure against modern TLS handshake sizes, suggested by @dpward
• Use unused retvals from functions in autossl
• Remove unused return value
• Fix recursive expansion in main.mk, thanks to @dpward
• Improve error handling and memory leak prevention in filter.c, for correctness, suggested and mostly implemented by Copilot
• Simplify platform check in main.mk for UserAuth feature
• Print version after unit tests in GitHub Actions