• Correct regression introduced in 5.6.0 where re-rendering components with the same root node could duplicate their DOM. Fixes #257.
• Enforce this.props and this.context, even when a class improperly inherits from Component (eg: calls super() without forwarding arguments)
• Fix for all empty vnodes ("", null, etc) rendering a comment - this should only occur when an empty vnode is returned from a component's render().
• Make event handler "on" prefix case-insensitive