fix crash when timerInterval is NaN in animateToProgress: method.

mrackwitz#108

Author: jaybowang

src/Components/MRCircularProgressView.m

@@ -231,6 +231,11 @@ - (void)animateToProgress:(float)progress {
     // Add timer to update valueLabel
     _valueLabelProgressPercentDifference = (progress - self.progress) * 100;
     CFTimeInterval timerInterval =  self.animationDuration / ABS(_valueLabelProgressPercentDifference);
+
+    if (isnan(timerInterval)) {
+        timerInterval = self.animationDuration;
+    }
+
     self.valueLabelUpdateTimer = [NSTimer scheduledTimerWithTimeInterval:timerInterval
                                                                   target:self
                                                                 selector:@selector(onValueLabelUpdateTimer:)