Update the current variable before onNext on onPrev callback

[HaXxanParhar]

In Stories Progress View class, in the onFinishProgress move the onNext() and onPrev() callbacks after the start progress. We know Start progress is updating the current variable, so in the onNext callback the progressView object will have the old current (not the updated one). I'm loading images from the internet in the onNext and I want to pause the progessView until image is fully loaded. Here the problem is progressView is pointing to the old current value so I can't pause the progressView for the next (or previous) image. Right now I'm going to clone the repository and make these changes in it, I don't know how to contribute to your library. But once you've made the above-mentioned changes, I'll switch back. Thanks