Fixes and improvements
- RTSP client: do not return a timeout error in case UDP packets are being received from a single track
- RTSP client: fix channel of RTCP packets, avoiding client timeouts
- RTSP source: support RTP-Info headers with paths instead of URLs (#250)
- RTSP source: support RTP-Infos with spaces (#333)
- RTMP client: fix client removal after an error