Flux todomvc enhancements from justin

2 minor changes:

1. Enable react chrome dev tools.
2. Smaller methods.
@zpao I'm happy to put the code back into render. My goal was to try to slim down the method size. What's do you reckon is the best way to do that? Or maybe a longer method is preferable? (wouldn't typically be in the Ruby world, FWIW, where we try to keep methods down to 10 lines or less).