3.8.1

• Revert an unintentionally breaking change from 3.8.0 where undefined vnodes throw an exception. Expect this behavior in the future, but for now they will once again render as <undefined>. (#59 / #61, thanks @billneff79)
• Fix defaultProps to work the same way it does in Preact on the client (#60, thanks @ftes)
• Ensure type definition is included in the npm package (#51, thanks @pspeter3)