fixed bad-looking icon issue on windows

systray_windows.go

@@ -183,6 +183,7 @@ type winTray struct {
 func (t *winTray) setIcon(src string) error {
 	const IMAGE_ICON = 1               // Loads an icon
 	const LR_LOADFROMFILE = 0x00000010 // Loads the stand-alone image from the file
+	const LR_DEFAULTSIZE = 0x00000040  // Loads default-size icon for windows(16 x 16) if cx, cy are set to zero
 	const NIF_ICON = 0x00000002
 
 	// Save and reuse handles of loaded images
@@ -196,9 +197,9 @@ func (t *winTray) setIcon(src string) error {
 			0,
 			uintptr(unsafe.Pointer(srcPtr)),
 			IMAGE_ICON,
-			64,
-			64,
-			LR_LOADFROMFILE,
+			0,
+			0,
+			LR_LOADFROMFILE|LR_DEFAULTSIZE,
 		)
 		if res == 0 {
 			return err