change generateMusic signature + delete second_melody

signature to get usefull infos
second_melody too confusing for gameplay

SimpleGame/src/Include/AudioEmitter.hpp

@@ -1,6 +1,7 @@
 #include <fmod.hpp>
 #include <fmod_errors.h>
 #include <memory>
+#include <utility>
 #include <vector>
 
 class AudioEmitter {
@@ -22,7 +23,7 @@ private:
 
 public:
   AudioEmitter();
-  void generateMusic();
+  std::vector<std::pair<float, int>> generateMusic();
   void audioUpdate();
   void audioEnd();
   int firstChord();