Use http instead of https in gvctrl getLogin request. Gave RTP client a close method so that the conn can
be closed after we're done with the client. Put timeout on reading from the RTP client PacketConn so that
we don't hang on the ReadFrom call if the conn is closed. Closing the RTSP and RTP clients when
startRTSPCamera is returned.
Added required new params to config structure, and therefore also added new defaults and validation checking.
Also updated revid's update func so that we can control new parameters using vars. Now using gvctrl in
startRTSPCamera function and interpreting revid config to configure camera.
Saxon