add some app infrastructure services

src/synth/AudioEngine.hpp

@@ -5,6 +5,9 @@
 
 #include <RtAudio.h>
 
+#include "LoggerService.hpp"
+
+
 #if defined(_WIN32)
     #define AUDIO_API RtAudio::WINDOWS_WASAPI
 #else
@@ -15,7 +18,7 @@ class AudioEngine {
 
 public:
 
-    AudioEngine();
+    AudioEngine(LoggerService* logger);
     ~AudioEngine();
 
     bool start();
@@ -36,4 +39,6 @@ private:
 
     float phase_ = 0.0f;
 
+    LoggerService* logger_;
+
 };