Fixed Device source by enabling/disabling the sync option of GstAppSink

depending on the live mode of the pipeline (detected at pipeline first
status change). Cleanup and unified info debug messages of all stream
sources.

Stream.h

@@ -29,7 +29,7 @@ public:
     /**
      * Open a media using gstreamer pipeline keyword
      * */
-    void open(const std::string &gstreamer_description );
+    void open(const std::string &gstreamer_description);
     /**
      * Get description string
      * */
@@ -60,7 +60,7 @@ public:
     /**
      * True if enabled
      * */
-    bool isEnabled() const;
+    bool enabled() const;
     /**
      * True if its an image
      * */
@@ -108,6 +108,8 @@ public:
      * */
     void accept(Visitor& v);
 
+    int id() const;
+
 protected:
 
     // video player description