Adding Behavior for Slider.js.

This might be a little easier if you subclassed Slider. You'd literally just yank this chunk and drop it into a new Class that extends Slider and reference `this.targets` instead of `targets` so it wouldn't be a lot of work. But then you could un-nest some of these functions in your iterations. You'd have a function that updates a target, and another function that given an operator and a target's modifier updates its value, etc.

```javascript
Slider.Inputs = new Class({
  Extends: Slider,
  options: {
    targets: [{...},{...}]
  },
  getTargets: function(){
     this.targets = this.options.targets.each(fn);
  },
  updateTarget: function(target){
  },
  updateCount: function(count, operator, modifier){
  }
});
```

Cleaner, IMHO.