Device GUIs: Constain window size via minimumSize/maximumSize, rather than handling resizeEvent. Add maximum button. Hide size buttons when window size is fixed

plugins/samplesource/airspy/airspygui.cpp

@@ -18,7 +18,6 @@
 #include <QDebug>
 #include <QMessageBox>
 #include <QFileDialog>
-#include <QResizeEvent>
 
 #include <libairspy/airspy.h>
 
@@ -48,7 +47,7 @@ AirspyGui::AirspyGui(DeviceUISet *deviceUISet, QWidget* parent) :
     m_sampleSource = (AirspyInput*) m_deviceUISet->m_deviceAPI->getSampleSource();
 
     ui->setupUi(getContents());
-    setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
+    sizeToContents();
     getContents()->setStyleSheet("#AirspyGui { background-color: rgb(64, 64, 64); }");
     m_helpURL = "plugins/samplesource/airspy/readme.md";
 	ui->centerFrequency->setColorMapper(ColorMapper(ColorMapper::GrayGold));
@@ -109,12 +108,6 @@ bool AirspyGui::deserialize(const QByteArray& data)
 	}
 }
 
-void AirspyGui::resizeEvent(QResizeEvent* size)
-{
-    adjustSize();
-    size->accept();
-}
-
 bool AirspyGui::handleMessage(const Message& message)
 {
     if (AirspyInput::MsgConfigureAirspy::match(message))