sniproxy 0.9.24

• Feature: Add -t flag to test configuration and exit without starting the
  proxy, similar to nginx -t. Reports whether the config file is valid.
• Feature: Add -g flag to allow group-read (0640) config file permissions.
  After privilege drop the unprivileged process cannot re-read a root-owned
  0600 config file, causing SIGHUP reload to fail. The -g flag relaxes the
  permission check to accept 0640 while still rejecting group-write,
  group-exec, and all other access. A security warning is logged at startup.
• Improved config permission error messages to show the maximum allowed mode
  and hint about the -g flag when applicable.