Implement "Speed" option on RTSP "PLAY" command by Changing Live555 Code
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Architecture:
* Live555 RTSP stack is used by the client component of UTC's Prism surveillance product.
* In particular, the streaming driver (session_lnvr.dll) of Prism client uses this open source software.
* The driver statically links the Live555 library.
* The driver communicates with the Live555 RTSP stack via RTSPAsyncAdapter, which is based
      on testRTSPClient demo application of Live555 but significantly modified to fit UTC architecture.

* RTSPAsyncAdapter modules (United Technologies Corp) included in the attached zip file
  (along with Live555 modules):
     RTSPAsyncAdapter.cpp
     RTSPAsyncAdapter.h
     
* Version of Live555 source used:
     "2015.05.31"
     
* Changes to Live555 code are limited to
     liveMedia/include/MediaSession.hh,
     liveMedia/include/RTSPClient.hh, and
     liveMedia/RTSPClient.cpp

* This version of Live555 ("2015.05.31") is integrated into UTC Prism surveillance product and tested
     for "Speed:" option support. The changes worked.

Change Details:
1. RTSPClient.cpp:
   * Implement new method, void RTSPClient::setSpeed(MediaSession& session, float speed)
   * Implement new method, static char* createSpeedString(float speed)
   * Enhance method, RTSPCLient::setRequestFields() method to add 'Speed:" option to PLAY command
   * Implement new method, Boolean RTSPClient::parseSpeedParam(char const* paramStr, float& speed)
         to process 'Speed' parameter in response
   * Enhance RTSPClient::handlePLAYResponse() method to handle 'Speed:" option
   * Initialize & retrieve speedParamsStr in RTSPClient::handleResponseBytes() method

2. RTSPClient.hh:
   * Declare new method, void RTSPClient::setSpeed(MediaSession& session, float speed) to
         set speed property in MediaSession and MediaSubsession objects.
   * Declare new method, Boolean RTSPClient::parseSpeedParam(char const* paramStr, float& speed);
   * Modify declaration of method, Boolean RTSPClient::handlePLAYResponse(MediaSession& session, MediaSubsession& subsession,
                             char const* scaleParamsStr, char const* rangeParamsStr, char const* rtpInfoParamsStr, const char* speedParamsStr);

3. MediaSession.hh:
   * Define 'fSpeed' property and implement new method, float& MediaSession::speed() to access it.
   * Define 'fSpeed' property and implement new method, float& MediaSubsession::speed() to access it.