Restored outputScale. My mistakegit add output_i2s_f32.h

output_i2s_f32.h

@@ -55,6 +55,12 @@ public:
 		audio_block_samples = settings.audio_block_samples;
 		begin();
 	}
+
+    // outputScale is a gain control for both left and right.  If set exactly
+    // to 1.0f it is left as a pass-through.
+    void setGain(float _oscale) {
+       outputScale = _oscale;
+       }
 	virtual void update(void);
 	void begin(void);
 	void begin(bool);
@@ -101,6 +107,7 @@ private:
 	static float sample_rate_Hz;
 	static int audio_block_samples;
 	volatile uint8_t enabled = 1;
+    float outputScale = 1.0f;  // Quick volume control
 };
 
 class AudioOutputI2Sslave_F32 : public AudioOutputI2S_F32