Set the actually opened audio device from vatlib

In the past, the optional arguments currentInput and currentOutput were not
used. Therefore we never knew which device was actually opened by vatlib.
This caused the Audio UI to be completely unsychronized from the reality
when loading swiftgui.

ref T337

src/blackmisc/audio/audiodeviceinfolist.cpp

@@ -36,6 +36,11 @@ namespace BlackMisc
             return this->findBy(&CAudioDeviceInfo::getType, CAudioDeviceInfo::InputDevice);
         }
 
+        CAudioDeviceInfo CAudioDeviceInfoList::findByDeviceIndex(int deviceIndex)
+        {
+            return this->findBy(&CAudioDeviceInfo::getIndex, deviceIndex).frontOrDefault();
+        }
+
         int CAudioDeviceInfoList::count(CAudioDeviceInfo::DeviceType type) const
         {
             return std::count_if(this->begin(), this->end(), [type](const CAudioDeviceInfo &device)

src/blackmisc/audio/audiodeviceinfolist.h

@@ -44,6 +44,9 @@ namespace BlackMisc
             //! Get output devices in that list
             CAudioDeviceInfoList getInputDevices() const;
 
+            //! Find device by its index
+            CAudioDeviceInfo findByDeviceIndex(int deviceIndex);
+
             //! Count (as of type)
             int count(CAudioDeviceInfo::DeviceType type) const;
         };