if badgeValue is "0",badgeLabel still exist ! UIButton+badge

[koalahl]

hi, the judgement of badgeValue in setBadgeVaule method is wrong!.

I sepearate it in two judgements:
// When changing the badge value check if we need to remove the badge
if (!badgeValue || [badgeValue isEqualToString:@""]) {

    [self removeBadge];
}else if ([badgeValue isEqualToString:@"0"]){// && self.shouldHideBadgeAtZero error。

    [self removeBadge];
}

or if (badgeValue || [badgeValue isEqualToString:@""] || [badgeValue isEqualToString:@"0"] &&self.shouldHideBadgeAtZero )