title: Simple way to check if redux state changed
body: <p>I have a story reducer with state that constantly changes based on actions that users perform, I'd like to show "Save changes" indicator when story gets changed and the only way I can think about to do this is to attach something to each action that changes state to know if it was performed hence affected state of the story. However, I have a lot of these and it would be better if there was a simple way to check if redux state changed and show "Save changes" indicator based on that.</p>