Review Feedback, Form and other control apis design.

[metasansana]

APIs like setMessage() and setValidationState() were designed with a specific project in mind. Now that we have more experience with this library, it may be a good idea to review how these are implemented, make them more consistent and fun to work with.

[metasansana]

The setValidataionState() should probably be kept, there are times we need to change the state of the control without setting a message. However instead of having to do setMessage(msg) then setValidationState(), it would be easier to just call setErrorMessage(msg) or something to that effect.

[metasansana]

Buttons should not be generic. Clicking on a button should fire an event but not provide a value. If a value needs to be provided use a closure.