FIX: Inactive demod bendwiths are restored to 0 from sessions, because they were erroneously saved as such.

The problem lies in DemodulatorPreThread:
- settings were actually get/set unprotected from concurrent access (bendwiths, frequencies, sample rates...etc) so make them atomic.
- If bandwith has changed, return the new value instead of the current one, just like frequencies.

src/demod/DemodulatorMgr.cpp

@@ -385,7 +385,7 @@ void DemodulatorMgr::setOutputDevices(std::map<int,RtAudio::DeviceInfo> devs) {
 
 void DemodulatorMgr::saveInstance(DataNode *node, DemodulatorInstance *inst) {
     *node->newChild("bandwidth") = inst->getBandwidth();
-    *node->newChild("frequency") = inst->getFrequency();
+    *node->newChild("frequency") = inst->getFrequency();  
     *node->newChild("type") = inst->getDemodulatorType();
     
     node->newChild("user_label")->element()->set(inst->getDemodulatorUserLabel());

src/demod/DemodulatorPreThread.cpp

@@ -76,7 +76,7 @@ void DemodulatorPreThread::run() {
         iqInputQueue->pop(inp);
         
         if (frequencyChanged.load()) {
-            currentFrequency = newFrequency;
+            currentFrequency.store(newFrequency);
             frequencyChanged.store(false);
         }
         
@@ -326,7 +326,11 @@ void DemodulatorPreThread::setBandwidth(int bandwidth) {
     newBandwidth = bandwidth;
 }
 
-int DemodulatorPreThread::getBandwidth() {    
+int DemodulatorPreThread::getBandwidth() {
+    if (bandwidthChanged.load()) {
+        return newBandwidth;
+    }
+
     return currentBandwidth;
 }
 

src/demod/DemodulatorPreThread.h

@@ -5,6 +5,7 @@
 
 #include <queue>
 #include <vector>
+#include <atomic>
 
 #include "CubicSDRDefs.h"
 #include "DemodDefs.h"
@@ -56,10 +57,10 @@ protected:
     Modem *cModem;
     ModemKit *cModemKit;
     
-    long long currentSampleRate, newSampleRate;
-    long long currentFrequency, newFrequency;
-    int currentBandwidth, newBandwidth;
-    int currentAudioSampleRate, newAudioSampleRate;
+    std::atomic_llong currentSampleRate, newSampleRate;
+    std::atomic_llong currentFrequency, newFrequency;
+    std::atomic_int currentBandwidth, newBandwidth;
+    std::atomic_int currentAudioSampleRate, newAudioSampleRate;
 
     std::atomic_bool sampleRateChanged, frequencyChanged, bandwidthChanged, audioSampleRateChanged;