Player: 添加kWaitTrackReady选项决定播放器是否等待所有track ready再回调

src/Common/config.cpp

@@ -306,6 +306,7 @@ const string kTimeoutMS = "protocol_timeout_ms";
 const string kMediaTimeoutMS = "media_timeout_ms";
 const string kBeatIntervalMS = "beat_interval_ms";
 const string kBenchmarkMode = "benchmark_mode";
+const string kWaitTrackReady = "wait_track_ready";
 }
 
 }  // namespace mediakit