Add an ATR to a reader node.

def AddATR(self, readernode, atr):
        """Add an ATR to a reader node."""
        capchild = self.AppendItem(readernode, atr)
        self.SetPyData(capchild, None)
        self.SetItemImage(
            capchild, self.cardimageindex, wx.TreeItemIcon_Normal)
        self.SetItemImage(
            capchild, self.cardimageindex, wx.TreeItemIcon_Expanded)
        self.Expand(capchild)
        return capchild