Add DialogPositioner to ensure dialogs are fully on screen and remain on

screen when screen orientation changes.
Add DialPopup to allow dials to adjusted with a slider, which is easier
on touchscreens.
Add TableTapAndHold to support table context menus on touchscreens.

plugins/samplesource/soapysdrinput/soapysdrinputgui.cpp

@@ -27,6 +27,7 @@
 #include "util/simpleserializer.h"
 #include "gui/glspectrum.h"
 #include "gui/basicdevicesettingsdialog.h"
+#include "gui/dialogpositioner.h"
 #include "soapygui/discreterangegui.h"
 #include "soapygui/intervalrangegui.h"
 #include "soapygui/stringrangegui.h"
@@ -936,6 +937,7 @@ void SoapySDRInputGui::openDeviceSettingsDialog(const QPoint& p)
         dialog.setReverseAPIDeviceIndex(m_settings.m_reverseAPIDeviceIndex);
 
         dialog.move(p);
+        new DialogPositioner(&dialog, false);
         dialog.exec();
 
         m_settings.m_useReverseAPI = dialog.useReverseAPI();