Update built-in cursors. (#246)

- Not all Qt::CursorShapes are supported on all platforoms
   - e.g. on Wayland (Ubuntu 24.04) Qt::SizeAllCursor is not available and
     falls back to its arrow cursor
   - added built-in Crosshair and Move cursors, so that they should be available
     across all platforms
- Redesigned existing object creation cursors
   - Crosshairs are now 3-pixels wide
   - Added white outlines to all cursors to aid in visibility against diverse
     backgrounds

glabels/Cursors.h

@@ -35,6 +35,20 @@ namespace glabels
 	{
 
 		
+		class Crosshair : public QCursor
+		{
+		public:
+			Crosshair();
+		};
+
+
+		class Move : public QCursor
+		{
+		public:
+			Move();
+		};
+
+
 		class Barcode : public QCursor
 		{
 		public: