cDemux: add dummy SetSource() for coolstream compatibiliy

libtriple/dmx_td.h

@@ -60,6 +60,8 @@ class cDemux
 		bool addPid(unsigned short pid);
 		void getSTC(int64_t * STC);
 		int getUnit(void);
+		/* tripledragon is unlikely to get a second tuner, so stub it out right here */
+		static bool SetSource(int /*unit*/, int /*source*/) { return true; };
 		// TD only functions
 		int getFD(void) { return fd; };		/* needed by cPlayback class */
 		void removePid(unsigned short Pid);	/* needed by cRecord class */