Stop thread if still running in destructor

Threads addressed in this commit:
 - Transmitter (txThread, txStats)
 - Capturer
 - EmulXcvr

server/pcapport.cpp

@@ -401,6 +401,8 @@ PcapPort::PortCapturer::PortCapturer(const char *device)
 
 PcapPort::PortCapturer::~PortCapturer()
 {
+    if (isRunning())
+        stop();
     capFile_.close();
 }
 
@@ -549,6 +551,7 @@ PcapPort::EmulationTransceiver::EmulationTransceiver(const char *device,
 
 PcapPort::EmulationTransceiver::~EmulationTransceiver()
 {
+    if (isRunning())
         stop();
 }
 
@@ -738,7 +741,7 @@ void PcapPort::EmulationTransceiver::stop()
             QThread::msleep(10);
     }
     else {
-        qWarning("Receive stop requested but is not running!");
+        qWarning("Emulation Xcvr stop requested but is not running!");
         return;
     }
 }

server/pcaptransmitter.cpp

@@ -34,6 +34,10 @@ PcapTransmitter::PcapTransmitter(
 
 PcapTransmitter::~PcapTransmitter()
 {
+    if (txThread_.isRunning())
+        txThread_.stop();
+    if (txStats_.isRunning())
+        txStats_.stop();
 }
 
 bool PcapTransmitter::setRateAccuracy(