ReactTools is deprecated, it doesn't belong at the root of the project. We'll remove it after 0.14 but for now this moves it so that it's contained and not intermixed with the rest of the project. The currect behavior of copying src/ into the package is maintained.
This reworks a few things in building and distributing React. The biggest change is using fbjs to share dependencies with other libraries. We're also using Gulp for some build steps.
The addons module warning is currently causing issues with babel/JSPM due to the warning message getting parsed as a require statement. Adding a break using string concatenation appears to prevent any issues.
Example error using JSPM:
```
Error loading "react-addons-{addon}" from...
```
- Add missing object-assign dependency
- Add batchedUpdates to ReactDOMClient, rename the two addons to `unstable_`
- Delete react/addons/* (leaving react/addons with a slightly updated warning)
- Add README.md, LICENSE, PATENTS to each addons package
