网络请求的中文解码，如今iOS9已经将如下解码方式砍了，原因是有些特殊字符串无法识别
url = [url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
替换为如下代码:
url = [url stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSetcharacterSetWithCharactersInString:@"`#%^{}\"[]|\\<> "].invertedSet];
