Use React.render instead of React.renderComponent in README

React.renderComponent has been deprecated in React 0.12. I think that it's
a better example with the latest React.
Merge pull request #32 from okuryu/readme-react-0.12

Use React.render instead of React.renderComponent in README
Improve sourcemaps

This improves source maps, but including a `sourceRoot` value, and
generating source maps for `react-intl-with-locales.js`.

**Note:** This should be merged _after_ these two PRs:

- https://github.com/caridy/grunt-bundle-jsnext-lib/pull/7
- https://github.com/caridy/grunt-bundle-jsnext-lib/pull/8
Upgrade dev deps for computing better sourcemaps
Merge pull request #33 from ericf/improve-sourcemaps

Improve sourcemaps
Build with improved sourcemaps