Update to upstream version 2020.03.06

Details: Upstream changelog since last ports version:
2020.03.06:

• Fixed a problem in "H264or5VideoStreamFramer.cpp" that was allegedly causing problems compiling for Windows.

2020.02.25:

• Added full support for the "LIVE555 HLS Proxy" ("live555HLSProxy") application, which is documented at: http://live555.com/hlsProxy/

2020.02.24:

• Commented out a line of code that was preventing "RTSPClientConnection" objects from being closed when a RTSP server handles a "TEARDOWN" command (on a RTP-over-TCP stream).

2020.02.23:

• Updated our (unicast) RTSP server implementation to handle "PAUSE" commands by calling "stopGettingFrames()" on the input source. Normally, this is just a no-op, but might not be for some input sources. (See below.)
• Fixed a bug in "H264or5VideoStreamFramer" that was causing it to not update its presentation times properly following a pause. (Thanks to Micha Kalfon for reporting this.)
• Updated "openRTSP" to improve the handling of the "-R <port-num>" option. If the specified port number cannot be used (e.g., because it's already in use), then "openRTSP" now exits.