collapse requires

This uses my fork of bundle-collapser to catch `_dereq_`. I'm going to try to get that upstreamed.

```
   raw     gz Sizes
397097  79877 build/JSXTransformer.js
525695 125006 build/react-with-addons.js
120910  34456 build/react-with-addons.min.js
480396 114182 build/react.js
112073  32094 build/react.min.js

   raw     gz Compared to last run
-20183  -3806 build/JSXTransformer.js
-125430 -9021 build/react-with-addons.js
-15766  -2982 build/react-with-addons.min.js
-112805 -7773 build/react.js
-14753  -2736 build/react.min.js
```