Provide direction property in onHighlightChange event.
Make MenuListInspector's moveCursor method return false instead of throwing an exception when no child menu list is found. Arguably this is an API-breaking change, but we're not bumping the major version number here because of the current unlikelihood that any users are depending on this now.
Add a small delay before a submenu opens when the user hovers over a SubMenuItem. This makes SubMenuItem's behavior more consistent with OS X dropdown menus, and seems to make the submenu's appearance seem less jarring to the user.