Fix crash in changing fast items. (#6)

Fix crash in changing fast items (-1 or > count position)

Author: sajjadintel

library/src/main/java/cz/intik/overflowindicator/OverflowPagerIndicator.java

@@ -120,6 +120,10 @@ private void updateOverflowState(int position) {
 			return;
 		}
 
+		if(position < 0 || position > mIndicatorCount){
+			return;
+		}
+
 		Transition transition = new TransitionSet()
 				.setOrdering(TransitionSet.ORDERING_TOGETHER)
 				.addTransition(new ChangeBounds())