Add need_cleanup flag for reverb

The cleanup() overwrites about 120kbytes of memory, which may affect the GUI speed on slower PIs. It is better to run it before audio processing.

src/effect_platervbstereo.cpp

@@ -228,6 +228,12 @@ void AudioEffectPlateReverb::doReverb(const float32_t* inblockL, const float32_t
 
     rv_time = rv_time_k;
 
+    if (need_cleanup)
+    {
+        cleanup();
+        need_cleanup = false;
+    }
+
     for (uint16_t i=0; i < len; i++) 
     {
         // do the LFOs

src/effect_platervbstereo.h

@@ -106,8 +106,10 @@ public:
 
     float32_t get_size(void) {return rv_time_k;}
     float32_t get_level(void) {return reverb_level;}
+    void set_need_cleanup(void) {need_cleanup = true;};
     void cleanup(void);
 private:
+    bool need_cleanup = false;
     float32_t reverb_level;
     float32_t input_attn;
 

src/minidexed.cpp

@@ -1015,7 +1015,7 @@ void CMiniDexed::SetParameter (TParameter Parameter, int nValue)
 		nValue=constrain((int)nValue,0,1);
 		m_ReverbSpinLock.Acquire ();
 		if (nValue)
-			reverb->cleanup ();
+			reverb->set_need_cleanup ();
 		m_ReverbSpinLock.Release ();
 		break;