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

SSLproxy