Support defaultProps in AutoControlledComponent

[levithomason]

This was fixed for the Accordion but likely exists in other auto controlled components.

From #763:

The defaultActiveIndex is overridden in the Accordion on componentWillMount. This is an edge case, but we need to update the AutoControlledComponent to defer to default props when calling trySetState in componentWillMount.

The real solve here is likely adding static defaultAutoControlledProps. Currently, the AutoControlledComponent tells devs to use trySetState in componentWillMount instead of setting defaults for auto controlled props. This is to prevent the actual defaults from always winning, however, if we had our own auto controlled defaults then we could apply them correctly.