Save sample rate, gain levels and AGC state per-device, add sample rate to device dialog

src/AppFrame.cpp

@@ -1597,7 +1597,9 @@ bool AppFrame::loadSession(std::string fileName) {
 
         long long center_freq = *header->getNext("center_freq");
         std::cout << "\tCenter Frequency: " << center_freq << std::endl;
-        
+
+        wxGetApp().setFrequency(center_freq);
+
         if (header->hasAnother("sample_rate")) {
             int sample_rate = *header->getNext("sample_rate");
             
@@ -1613,8 +1615,6 @@ bool AppFrame::loadSession(std::string fileName) {
             
         }
 
-        wxGetApp().setFrequency(center_freq);
-
         DataNode *demodulators = l.rootNode()->getNext("demodulators");
 
         int numDemodulators = 0;