Tracker: Add some zoom padding in list mode

Add some padding to the right and bottom of the content when
you zoom.

16px the size of a mini-icon

src/kits/tracker/ContainerWindow.cpp

@@ -1352,6 +1352,10 @@ BContainerWindow::ResizeToFit()
 	frame.right = frame.left + extent.Width() + widthDiff;
 	frame.bottom = frame.top + extent.Height() + heightDiff;
 
+	// add some padding to the right and bottom
+	frame.right += be_control_look->DefaultItemSpacing() * 2;
+	frame.bottom += be_control_look->DefaultItemSpacing() * 2;
+
 	// make sure entire window fits on screen
 	frame = frame & screenFrame;