Source creation by origin: File, software and hardware. Separate source

classes for Media and Session sources. Update of file dialog
accordingly.

Mixer.h

@@ -1,7 +1,6 @@
 #ifndef MIXER_H
 #define MIXER_H
 
-#include <vector>
 
 //  GStreamer
 #include <gst/gst.h>
@@ -11,6 +10,7 @@
 #include "Session.h"
 #include "Source.h"
 
+
 class Mixer
 {
     // Private Constructor
@@ -34,7 +34,7 @@ public:
     void draw();
 
     // manangement of sources
-    void createSourceMedia(std::string path);
+    void createSourceFile(std::string path);
 
     void deleteSource(Source *s);
     void deleteCurrentSource();