closes #8

some ui work

Source/shifter_voice.h

@@ -33,6 +33,7 @@ public:
 	float GetPanning(int channel) const;
 	int GetMidiNote() const { return current_midi; }
 	void SetPitchAdjust(float);
+	void SetPanWidth(float val) { pan_width = val; }
 	bool onoff_;
 
 	float panning;
@@ -48,5 +49,5 @@ private:
 	float current_amplitude;
 	float period_counter;
 	float pitch_adjust = 0.0f;
-	
+	float pan_width = 0.0f;
 };