Added preprocess for xml parse, extracted some variable and init in viewDidLoad

To make sure that the item to parse is the one we want (Cantonese Word of the Day).
    if ([mItem isEqualToString:@"title"]) {
        rangeStart = [tempString rangeOfString:@"Cantonese Word of the Day"];
        if (rangeStart.length != 0) {
            startParse = true;
        }
    }

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
    dataPath = [documentsDirectory stringByAppendingPathComponent:@"SoundStorage"];
    onlineSound = @"http://www.yueyv.cn/sound";