This introduces `ReactLink` which is a super lightweight way to do two-way binding for React.
If you want to use a controlled form input today, it's a lot of lines of code:
http://jsfiddle.net/T3z3v/
Look how many times `name` is repeated in there. And you have to remember to wire up event handles and pass the right state and
right event handler for *each* form field. It's really annoying.
With ReactLink, you can "link" a form value to a state field. It's just some simple sugar around the value prop/onChange
convention:
https://gist.github.com/petehunt/6689857
Ah, much nicer! And requires very little core changes or extra bytes. `ReactLink` just wraps the current value and "request
change" handler into a little object and provides some sugar to create some from composite component state.
Closes#250.
Test Plan:
With multiple and not, verified: With defaultValue, the correct option is picked initially, user changes change the selection, and changes to defaultValue have no effect. With value, the correct option is picked initially, user changes do nothing, and changes to value change the selection.
Also ran the tests.
This implements a `<select>` component that supports `value` and `defaultValue`. It also changes `<option>` to warn when the `selected` prop is supplied.
Andreas Svensson