Remove usages of C# 7.1 features

Author: MathewSachin

src/Captura.Windows/DesktopDuplication/DuplCapture.cs

@@ -73,7 +73,7 @@ public void Init()
             }
         }
 
-        public bool Get(Texture2D Texture, DxMousePointer DxMousePointer, Point TargetPosition = default)
+        public bool Get(Texture2D Texture, DxMousePointer DxMousePointer, Point TargetPosition = default(Point))
         {
             lock (_syncLock)
             {

src/Captura.Windows/DesktopDuplication/MousePointer/DXMousePointer.cs

@@ -77,7 +77,7 @@ public void Update(Texture2D DesktopTexture, OutputDuplicateFrameInformation Fra
             _pointerShape?.Update(DesktopTexture, _pointerPosition);
         }
 
-        public void Draw(Direct2DEditor Editor, Point Location = default)
+        public void Draw(Direct2DEditor Editor, Point Location = default(Point))
         {
             if (!_pointerPosition.Visible)
                 return;