added fill color property

After renaming the property to `circleFillColor`, can you rearrange the lines so it's like:

```
     self.circleColor = JWG_CIRCLE_COLOR_DEFAULT;
     self.circleBackgroundColor = JWG_CIRCLE_BACKGROUND_COLOR_DEFAULT;
     self.circleFillColor = JWG_CIRCLE_FILL_COLOR_DEFAULT;
     self.circleTimerWidth = JWG_CIRCLE_TIMER_WIDTH;
```