Release input devices when application is shutdown

If they are released with the deallocation of CInputManager, we might
run into global deallocation hell.
Also on Windows release all DirectX devices before COM library is closed.

ref T391

src/blackcore/inputmanager.cpp

@@ -129,6 +129,12 @@ namespace BlackCore
         m_lastCombination = combination;
     }
 
+    void CInputManager::releaseDevices()
+    {
+        m_keyboard.reset();
+        m_joystick.reset();
+    }
+
     int CInputManager::bindImpl(const QString &action, QObject *receiver, std::function<void (bool)> function)
     {
         static int index = 0;