Update to current version of React typings

 * The interfaces for react elements and factories are
   no longer part of the exports for the 'react' module
   but are instead part of the ambient 'React' module.

 * Typings for 'react/addons' are not included in
   react.d.ts, so there is no need to include add-on typings
   separately.

 * Enable email notifications so I get warnings if Travis fails
   to build in future.