Fixes and improvements
- General: add "error" log level
- General: print log levels with 3 characters, tidy up errors
- RTSP: make sourceFingerprint optional and allow standard validation of RTSPS server certificates
- RTSP: print exact reason when a session is destroyed (#649)
- HLS: allow disabling HTTPS validation by using sourceFingerprint (#665)
- API: sort arrays in configuration (#644)