keyboard waterfall zoom input tweaks

src/sdr/SDRPostThread.cpp

@@ -221,14 +221,14 @@ void SDRPostThread::run() {
         data_in->decRefCount();
     }
 
-    buffers.purge();
+//    buffers.purge();
     
     if (iqVisualQueue && !iqVisualQueue->empty()) {
         DemodulatorThreadIQData *visualDataDummy;
         iqVisualQueue->pop(visualDataDummy);
     }
 
-    visualDataBuffers.purge();
+//    visualDataBuffers.purge();
 
     std::cout << "SDR post-processing thread done." << std::endl;
 }

src/sdr/SDRThread.cpp

@@ -295,7 +295,7 @@ void SDRThread::run() {
         }
     }
 
-     buffers.purge();
+//     buffers.purge();
     
     std::cout << "SDR thread done." << std::endl;
 }