v4.0.0

Huge rewrite/refactor of the library!

Major Changes

• componentWillMount now gets executed before the visitor. This should allow for better initialized instances being passed into the visitor. This likely won't affect you, but it is good to be made aware of this change. Fixes the manner in which context is passed down the tree.: ef75192

Minor Changes

• Adds support for Preact (including "native" Preact - i.e. without preact-compat): ef75192
• Adds support for React's "Portals" feature.: ef75192

Patches

• Experimental componentWillUnmount calls now get executed after children resolved, and additionally no longer have their errors swallowed.: 687858c
• Ensures promise flow calls the componentWillUnmount in the correct order.: e7e049d