add animator reference to animatorDidStop ChartViewBase delegate callback.
add animator reference to animatorDidStop ChartViewBase delegate callback.

liuxuan30/ios-charts,danielgindi/ios-charts,jum/Charts,liuxuan30/Charts,liuxuan30/Charts,jjatie/Charts,MAARK/Charts,MAARK/Charts,danielgindi/ios-charts,danielgindi/Charts,jum/Charts,jjatie/Charts,jjatie/Charts,liuxuan30/ios-charts,jjatie/Charts,danielgindi/ios-charts,MAARK/Charts,danielgindi/ios-charts,liuxuan30/Charts,liuxuan30/ios-charts,jum/Charts,jum/Charts,liuxuan30/ios-charts,liuxuan30/Charts,MAARK/Charts,danielgindi/Charts,danielgindi/Charts,danielgindi/Charts