Added Master System Memory Bus

Core/Interfaces/IAudioDevice.cs

@@ -0,0 +1,8 @@
+namespace Core.Interfaces
+{
+    public interface IAudioDevice
+    {
+        // Now accepts the Beeper state + 3 AY frequencies + 3 AY volumes
+        void AddSample(bool isHigh, float freqA, float volA, float freqB, float volB, float freqC, float volC);
+    }
+}