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.cpp

@@ -26,6 +26,20 @@
 namespace glabels
 {
 
+	Cursors::Crosshair::Crosshair()
+		: QCursor( QPixmap(":cursors/32x32/cursor_crosshair.png"), 15, 15 )
+	{
+		// empty
+	}
+
+
+	Cursors::Move::Move()
+		: QCursor( QPixmap(":cursors/32x32/cursor_move.png"), 15, 15 )
+	{
+		// empty
+	}
+
+
 	Cursors::Barcode::Barcode()
 		: QCursor( QPixmap(":cursors/32x32/cursor_barcode.png"), 7, 7 )
 	{