Merging React and React with Addons

This seems simpler and enables developers to only require the addons
they want.
Cleanup react.d.ts; introduce Instance<P> interface to replace DomReferencer<P>; alias EventHandler types; etc...
ReactClass -> ComponentClass; add tests to react-tests.ts
Fill out HTMLAttributes types
Fill out React.SVGAttributes types
React.Instance<P> -> React.ElementInstance<P>
Change React.createFactory to take React.ComponentClass<P>
Fix React.ComponentInstance<P>.refs type and add some CSS properties
Merge pull request #3 from borisyankov/master

Merge borisyankov/DefinitelyTyped into Asana/DefinitelyTyped
Merge origin/master into react-simplification
Move Browser interfaces into React module
React.Instance<P> -> React.Component<P>; add React.DOM.picture and extra HTML attributes
Merge pull request #3259 from Asana/react-simplification

Refactor react.d.ts, merging with react-addons.d.ts