Flux todomvc enhancements from justin

2 minor changes:

1. Enable react chrome dev tools.
2. Smaller methods.
How do you feel about adding in lodash? The code for

```javascript
    var completed = 0;
    for (var key in allTodos) {
      if (allTodos[key].complete) {
        completed++;
      }
    }
```
could *probably* become (not tested however, [docs here](http://lodash.com/docs#filter) )

```
var completed = _.filter(allTodos, "complete").length;
```