PNBarChart crash if all yValues are 0.

[gbmksquare]

In the code below, if all values are 0, yValueMax tries to ge yMinValue. But since yMinValue is not initialized, the app crashes.

func getYValueMax(yLabels:NSArray) {
    let max:CGFloat = CGFloat(yLabels.valueForKeyPath("@max.floatValue") as! Float)
    if max == 0 {
        yValueMax = yMinValue
    } else{
        yValueMax = max
    }
}

Can be temporarily fixed by manually setting barChart.yMinValue when initializing.

[gbmksquare]

#26