Fixes and improvements
- General: close custom commands with SIGQUIT instead of SIGINT (#495)
- General: fill version correctly (#503)
- HLS: fix compatibility with video.js, iOS Safari, macOS Safari
- HLS, RTMP: print clearer error messages (#501)
- HLS: reply with 404 to invalid requests
- HLS: set default segment count to 3
- HLS: write PMT/PAT tables once at the beginning of every TS segment
- HLS: increase video size up to 100% of the page (#480)
- HLS: speed up loading by decreasing PTS
- HLS: send PCR once, at the beginning of every TS segment
- API: log requests and responses even in case of code 404
- API: log right protocol version of responses