Eliminate kXMLReaderTextNodeKey.

[YasufumiMuranaka]

<?xml version='1.0' encoding='utf-8'?>
<vcread>
    <bg_img id='32' title='背景(7)' x='0' y='0' width='320' height='480' src='333_07.jpg' tag='' seq='0' />
    <item>
        <text id='33' title='文本' x='19' y='309' width='284' height='166' type='char' content='ContentText'>
             TEST
        </text>
    </item>
    <text1>TEST1</text1>
    <text2 id='34'>TEST2</text2>
 </vcread>

(lldb) po result
{
    vcread =     {
        "bg_img" =         {
            height = 480;
            id = 32;
            seq = 0;
            src = "333_07.jpg";
            tag = "";
            title = "\U80cc\U666f(7)";
            width = 320;
            x = 0;
            y = 0;
        };
        item =         {
            text =             {
                content = ContentText;
                height = 166;
                id = 33;
                text = TEST;
                title = "\U6587\U672c";
                type = char;
                width = 284;
                x = 19;
                y = 309;
            };
        };
        text1 = TEST1;
        text2 =         {
            id = 34;
            text2 = TEST2;
        };
    };
}