v4.0.0-beta4

• All callbacks now have the port as this
• Disconnections now always attempt to close the port, and you'll always get a close event after a disconnect event
• Removed undocumented callbacks from the options object disconnectedCallback and dataCallback
• [unix] Ports are now locked by default with the new lock options matches windows default behavior
• [windows] known issue lock false doesn't work (no change in behavior)